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  • 1
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    Shallow velocity model in the area of Pozzo Pitarrone, Mt. Etna, from single station, array methods and borehole data. (2017)
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: Seismic noise recorded by a temporary array installed around Pozzo Pitarrone, NE flank of Mt. Etna, have been analysed with several techniques. Single station HVSR method and SPAC array method have been applied to stationary seismic noise to investigate the local shallow structure. The inversion of dispersion curves produced a shear wave velocity model of the area reliable down to depth of about 130 m. A comparison of such model with the stratigraphic information available for the investigated area shows a good qualitative agreement. Taking advantage of a borehole station installed at 130 m depth, we could estimate also the Pwave velocity by comparing the borehole recordings of local earthquakes with the same event recorded at surface. Further insight on the P-wave velocity in the upper 130 m layer comes from the surface reflected wave observable in some cases at the borehole station. From this analysis we obtained an average P-wave velocity of about 1.2 km/s, compatible with the shear wave velocity found from the analysis of seismic noise.
    Beschreibung: Published
    Beschreibung: S0433
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Etna volcano ; Velocity model ; Borehole station ; Seismic array ; SPAC method ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 2
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    PARTOS - Passive and Active Ray TOmography Software: description and preliminary analysis using TOMO-ETNA experiment’s dataset. (2017)
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: In this manuscript we present the new friendly seismic tomography software based on joint inversion of active and passive seismic sources called PARTOS (Passive Active Ray TOmography Software). This code has been developed on the base of two well-known widely used tomographic algorithms (LOTOS and ATOM-3D), providing a robust set of algorithms. The dataset used to set and test the program has been provided by TOMO-ETNA experiment. TOMO-ETNA database is a large, highquality dataset that includes active and passive seismic sources recorded during a period of 4 months in 2014. We performed a series of synthetic tests in order to estimate the resolution and robustness of the solutions. Real data inversion has been carried out using 3 different subsets: (i) active data; (ii) passive data; and (iii) joint dataset. Active database is composed by a total of 16,950 air-gun shots during 1 month and passive database includes 452 local and regional earthquakes recorded during 4 months. This large dataset provides a high ray density within the study region. The combination of active and passive seismic data, together with the high quality of the database, permits to obtain a new tomographic approach of the region under study never done before. An additional user-guide of PARTOS software is provided in order to facilitate the implementation for new users.
    Beschreibung: Published
    Beschreibung: S0435
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Seismic tomograpy ; Tomographic inversion code ; Mt. Etna volcano ; Seismology ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 3
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    TOMO-ETNA experiment at Etna volcano: Activities on land (2017)
    Details
    Publikationsdatum: 2022-04-29
    Beschreibung: In the present paper we describe the on-land field operations integrated in the TOMO-ETNA experiment carried out in June-November 2014 at Mt. Etna volcano and surrounding areas. This terrestrial campaign consists in the deployment of 90 short-period portable three-component seismic stations, 17 broadband seismometers and the coordination with 133 permanent seismic station belonging to Italy’s Istituto Nazionale di Geofisica e Vulcanologia (INGV). This temporary seismic network recorded active and passive seismic sources. Active seismic sources were generated by an array of air-guns mounted in the Spanish oceanographic vessel “Sarmiento de Gamboa” with a power capacity of up to 5200 cubic inches. In total more than 26,000 shots were fired and more than 450 local and regional earthquakes were recorded. We describe the whole technical procedure followed to guarantee the success of this complex seismic experiment. We started with the description of the location of the potential safety places to deploy the portable network and the products derived from this search (a large document including full characterization of the sites, owners and indication of how to arrive to them). A full technical description of the seismometers and seismic sources is presented. We show how the portable seismic network was deployed, maintained and recovered in different stages. The large international collaboration of this experiment is reflected in the participation of more than 75 researchers, technicians and students from different institutions and countries in the on-land activities. The main objectives of the experiment were achieved with great success.
    Beschreibung: Published
    Beschreibung: S0427
    Beschreibung: 2SR. VULCANI - Servizi e ricerca per la Società
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Active and passive seismic experiment ; Seismic tomography ; Etna volcano ; Oceanographic vessels ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 4
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    Active upper crust deformation pattern along the southern edge of the Tyrrhenian subduction zone (NE Sicily): Insights from a multidisciplinary approach (2016)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Using a multidisciplinary dataset based on gravimetric, seismic, geodetic and geological observations,we provide an improved picture of the shallow structure and dynamics of the southern edge of the Tyrrhenian subduction zone.With a local earthquake tomographywe clearly identify twomain crustal domains in the upper 15 kmcharacterized by different P-wave velocity values: a high-velocity domain comprising southeasternmost Tyrrhenian Sea, NE Sicily and Messina Straits, and a low-velocity domain comprising Mt. Etna and eastern Sicily. The transition between the two domains shows a good spatial correspondence with a wider set of faults including the Taormina Fault System (TFS) and the Aeolian–Tindari–Letojanni Fault System (ATLFS), two nearly SE-striking fault systems crossing northeastern Sicily and ending on the Ionian shoreline of Sicily according to many investigators. Within this set of faults, most of the deformation/seismicity occurs along the northern and central segments of ATLFS, compared to lowactivity along TFS. A lack of seismicity (both recent and historical) is observed in the southern sector of ATLFS where, however, geodetic data reveal significant deformation. Ourmultidisciplinary dataset including offshore observations suggests the southeastward continuation of the ATLFS into the Ionian Sea until joiningwith the faults cutting the Ionian accretionarywedge described in the recent literature. Our findings imply the existence of a highly segmented crustal shear zone extending from the Aeolian Islands to the Ionian Abyssal plain, that we believe plays the role of accommodating differential motion between the Southern Tyrrhenian unit and the western compressional domain of Sicily. The ATLFS, which is a main part of the inferred shear zone, behaves similarly to what often observed at the edges of retreating subduction
    Beschreibung: Published
    Beschreibung: 205-218
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Beschreibung: 1A. Geomagnetismo e Paleomagnetismo
    Beschreibung: 6A. Monitoraggio ambientale, sicurezza e territorio
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): subduction edge ; seismic velocity structure ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.03. Gravity and isostasy ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.05. Geomagnetism::04.05.99. General or miscellaneous ; 04. Solid Earth::04.05. Geomagnetism::04.05.03. Global and regional models ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 5
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    The deep structure of the Larderello-Travale geothermal field (Italy) from integrated, passive seismic investigations (2015)
    Elsevier
    Details
    Publikationsdatum: 2021-07-14
    Beschreibung: We report the preliminary results from a project (GAPSS-Geothermal Area Passive Seismic Sources), aimed at testing the resolving capabilities of passive exploration methods on a well-known geothermal area, namely the Larderello-Travale Geothermal Field (LTGF). Located in the western part of Tuscany (Italy), LTGF is the most ancient geothermal power field of the world. GAPSS consisted of up to 20 seismic stations deployed over an area of about 50 x 50 Km. During the first 12 months of measurements, we located more than 2000 earthquakes, with a peak rate of up to 40 shocks/day. Preliminary results from analysis of these signals include: (i) analysis of Shear-Wave-Splitting from local earthquake data, from which we determined the areal distribution of the most anisotropic regions; (ii) local-earthquake travel-time tomography for both P- and S-wave velocities; (iii) telesismic receiver function aimed at determining the high-resolution (〈0.5km) S-velocity structure over the 0-20km depth range, and seismic anisotropy using the decomposition of the angular harmonics of the RF data-set; (iv) S-wave velocity profiling through inversion of the dispersive characteristics of Rayleigh waves from earthquakes recorded at regional distances. After presenting results from these different analyses, we eventually discuss their potential application to the characterisation and exploration of the investigated area.
    Beschreibung: Published
    Beschreibung: 227-234
    Beschreibung: 6T. Sismicità indotta e caratterizzazione sismica dei sistemi naturali
    Beschreibung: N/A or not JCR
    Beschreibung: restricted
    Schlagwort(e): Geothermal field; Local Earthquake Tomography; Shear Wave Splitting; Surface Wave Dispersion; Receiver Functions; Larderello- Travale geothermal field (Italy) ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 6
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    Large-scale coherent anisotropy of upper mantle beneath the Italian peninsula comparing quasi-Love waves and SKS splitting (2015)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We document quantitatively observations of quasi-Love waves obtained at permanent (Italian National Seismic Network) and temporary seismic stations deployed in Italy between 2003 and 2006 (Retreat, CAT/SCAN projects). We analyzed large earthquakes with source parameters that favor quasi-Love wave generation within this time-span, including the Sumatra–Andaman earthquake of 12/26/04. The presence or the absence of the quasi-Love phase is compared to the smoothed anisotropic pattern defined by the numerous SKS splitting measurements obtained in peninsular Italy, and to the Italian upper mantle structure as defined by seismic tomography. The large-scale anisotropic features, responsible for shear-wave splitting and documented also by Pn and surface-wave anisotropy, generally display the correct geometry to explain the scattered quasi-Love waves. Quasi-Love observations do not demand a tilted-axis anisotropic geometry. We argue instead for anisotropy with laterally-variable horizontal symmetry axis in the upper mantle below the Italian peninsula.
    Beschreibung: Published
    Beschreibung: 26-38
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismic anisotropy ; Quasi-Love ; Italy ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 7
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    How to Invert Multi-Band, Regional Phase Amplitudes for 2-D Attenuation and Source Parameters: Tests Using the USArray (2015)
    Springer Verlag
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We inverted for laterally varying attenuation, absolute site terms, moments and apparent stress using over 460,000 Lg amplitudes recorded by the USArray for frequencies between 0.5 and 16 Hz. Corner frequencies of Wells, Nevada, aftershocks, obtained by independent analysis of coda spectral ratios, controlled the tradeoff between attenuation and stress, while independently determined moments from St. Louis University and the University of California constrained absolute levels. The quality factor, Q, was low for coastal regions and interior volcanic and tectonic areas, and high for stable regions such as the Great Plains, and Colorado and Columbia Plateaus. Q increased with frequency, and the rate of increase correlated inversely with 1-Hz Q, with highest rates in low-Q tectonic regions, and lowest rates in high-Q stable areas. Moments matched independently determined moments with a scatter of 0.2 NM. Apparent stress ranged from below 0.01 to above 1 MPa, with means of 0.1 MPa for smaller events, and 0.3 MPa for larger events. Stress was observed to be spatially coherent in some areas; for example, stress was lower along the San Andreas fault through central and northern California, and higher in the Walker Lane, and for isolated sequences such as Wells. Variance reduction relative to 1-D models ranged from 50 to 90 % depending on band and inversion method. Parameterizing frequency dependent Q as a power law produced little misfit relative to a collection of independent, multi-band Q models, and performed better than the omega-square source parameterization in that sense. Amplitude residuals showed modest, but regionally coherent patterns that varied from event to event, even between those with similar source mechanisms, indicating a combination of focal mechanism, and near source propagation effects played a role. An exception was the Wells mainshock, which produced dramatic amplitude patterns due to its directivity, and was thus excluded from the inversions. The 2-D Q plus absolute site models can be used for high accuracy, broad area source spectra, magnitude and yield estimation, and, in combination with models for all regional phases, can be used to improve discrimination, in particular for intermediate bands that allow coverage to be extended beyond that available for high frequency P-to-S discriminants.
    Beschreibung: Published
    Beschreibung: 469-484
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): 2-D Attenuation ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 8
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    ANISOMAT+: An automatic tool to retrieve seismic anisotropy from local earthquakes (2015)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: An automatic analysis code called ANISOMAT+ has been developed and improved to automatically retrieve the crustal anisotropic parameters fast polarization direction (ϕ) and delay time (δt) related to the shear wave splitting phenomena affecting seismic S-wave. The code is composed of a set of MatLab scripts and functions able to evaluate the anisotropic parameters from the three-component seismic recordings of local earthquakes using the cross-correlation method. Because the aim of the code is to achieve a fully automatic evaluation of anisotropic parameters, during the development of the code we focus our attention to devise several automatic checks intended to guarantee the quality and the stability of the results obtained. The basic idea behind the development of this automatic code is to build a tool able to work on a huge amount of data in a short time, obtaining stable results and minimizing the errors due to the subjectivity. These behaviors, coupled to a three component digital seismic network and a monitoring system that performs automatic pickings and locations, are required to develop a real-time monitoring of the anisotropic parameters.
    Beschreibung: Published
    Beschreibung: 62-68
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: 6T. Sismicità indotta e caratterizzazione sismica dei sistemi naturali
    Beschreibung: 3IT. Calcolo scientifico e sistemi informatici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): shear wave splitting, Earthquake forecast, Anisotropy, Cross-correlation method ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 9
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    Finite-difference P wave travel time seismic tomography of the crust and uppermost mantle in the Italian region (2015)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present a 3-D P wave velocity model of the crust and shallowest mantle under the Italian region, that includes a revised Moho depth map, obtained by regional seismic travel time tomography. We invert 191,850 Pn and Pg wave arrival times from 6850 earthquakes that occurred within the region from 1988 to 2007, recorded by 264 permanent seismic stations. We adopt a high-resolution linear B-spline model representation, with 0.1􏰂 horizontal and 2 km vertical grid spacing, and an accurate finite-difference forward calculation scheme. Our nonlinear iterative inversion process uses the recent European reference 3-D crustal model EPcrust as a priori information. Our resulting model shows two arcs of relatively low velocity in the crust running along both the Alps and the Apennines, underlying the collision belts between plates. Beneath the Western Alps we detect the presence of the Ivrea body, denoted by a strong high P wave velocity anomaly. We also map the Moho discontinuity resulting from the inversion, imaged as the relatively sharp transition between crust and mantle, where P wave velocity steps up to values larger than 8 km/s. This simple condition yields an image quite in agreement with previous studies that use explicit representations for the discontinuity. We find a complex lithospheric structure characterized by shallower Moho close by the Tyrrhenian Sea, intermediate depth along the Adriatic coast, and deepest Moho under the two mountain belts.
    Beschreibung: Published
    Beschreibung: 69-88
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): seismic tomography ; body waves ; computational seismology ; Moho topography ; Italy ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 10
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    La rete sismica AlpArray e il contributo dell'INGV (2015)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Il progetto AlpArray (PI E. Kissling, Seismology and Geodynamics ETH) è un’iniziativa europea di collaborazione interdisciplinare sismologica e geodinamica, il cui obiettivo principale è quello di migliorare la comprensione della struttura profonda e della geodinamica delle Alpi (la catena montuosa più studiata al mondo) tramite l’acquisizione, l’analisi e l’interpretazione di dati sismologici di alta qualità. Per ottenere delle immagini di estremo dettaglio della crosta e del mantello, AlpArray propone la realizzazione di una rete sismica a maglia il più possibile omogenea (massima distanza inter- stazione 52 km, backbone network), tramite la condivisione dei dati delle reti permanenti esistenti e l’installazione, da parte di ciascun paese partecipante, di numerose stazioni sismiche temporanee a larga banda (BB). Il progetto prevede l'installazione di circa 250 stazioni sismiche in tutta Europa, in particolare in Italia, Francia, Svizzera, Germania, Austria, Croazia, Repubblica Ceca, Bosnia, Ungheria, Slovenia e Polonia. I dati confluiranno all’interno dell’archivio europeo denominato European Integrated Data Archive (EIDA). Considerata l’estensione geografica dell’area, i partecipanti combineranno le infrastrutture esistenti per l’acquisizione dei dati, il loro trattamento, l’applicazione delle tecniche più avanzate di imaging e l’interpretazione e modellazione dei risultati, in uno sforzo transnazionale ad una scala mai realizzata prima in Europa. Si tratta quindi di un’occasione fondamentale per lo scambio di competenze tecniche e scientifiche all’avanguardia. L’INGV, oltre a condividere i dati delle proprie stazioni permanenti nell’area di interesse, si occupa della installazione e della manutenzione sul territorio italiano di 20 nuove stazioni-BB temporanee i cui dati verranno trasmessi in tempo reale (partecipando così alla realizzazione del backbone) e coadiuva l’ETH nella ricerca dei siti italiani per altrettante stazioni svizzere e nella loro manutenzione ordinaria. L’acquisizione di una mole notevole di nuovi dati permetterà di raffinare le conoscenze sulla struttura e la composizione della litosfera e del mantello al di sotto dell’area alpina: Queste conoscenze sono anche utili ai fini della modellazione geodinamica. Il potenziamento del monitoraggio sismico aiuterà ad individuare e studiare in maggior dettaglio le aree sismogenetiche della regione alpina.
    Beschreibung: Published
    Beschreibung: Trieste
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: open
    Schlagwort(e): AlpArray ; seismic network ; Rete sismica ; Alpi ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 11
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    New insights into crustal structure, Cenozoic magmatism, CO2 degassing and seismogenesis in the southern Apennines and Irpinia region from local earthquake tomography (2015)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present high-resolution Vp and Vp/Vs models of the southern Apennines (Italy) computed using local earthquakes recorded from 2006 to 2011 with a graded inversion scheme that progressively resolves the crustal structure, from the large scale of the Apennines belt to the local scale of the normal-fault system. High-Vp bodies defined in the upper and mid crust under the external Apennines are interpreted as extensive mafic intrusions revealing anorogenic magmatism episodes that broadened on the Adriatic domain during Paleogene. Under the mountain belt, a low-Vp region, annular to the Neapolitan volcanic district, indicates the existence of a thermal/fluid anomaly in the mid crust, coinciding with a shallow Moho and diffuse degassing of deeply derived CO2. In the belt axial zone, low Vp/Vs gas-pressurized rock volumes under the Apulian carbonates correlate to high heat flow, strong CO2-dominated gas emissions of mantle origin and shallow carbonate reservoirs with pressurized CO2 gas caps. We hypothesize that the pressurized fluid volumes located at the base of the active fault system influence the rupture process of large normal-faulting earthquakes, like the 1980 Mw6.9 Irpinia event, and that major asperities are confined within the high-Vp Apulian carbonates. This study confirms once more that pre-existing structures of the Pliocene Apulian belt controlled the rupture propagation during the Irpinia earthquake. The main shock broke a 30 km long, NE-dipping seismogenic structure, whereas delayed ruptures (both the 20 s and the 40 s sub-events) developed on antithetic faults, reactivating thrust faults located at the eastern edge of the Apulian belt.
    Beschreibung: Published
    Beschreibung: 8283–8311
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: JCR Journal
    Beschreibung: embargoed_20150609
    Schlagwort(e): The velocity structure of the southern Apennines is determined by a multi-scale tomography ; Large Cenozoic mafic intrusions are identified in the Apulian crust ; Pressurized CO2 reservoirs identified under the axial belt can affect crustal seismicity ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    Two-dimensional seismic attenuation images of Stromboli Island using active data (2015)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In this work we present intrinsic and scattering seismic attenuation 2-D images of Stromboli Volcano. We used 21,953 waveforms from air gun shots fired by an oceanographic vessel and recorded at 33 inland and 10 ocean bottom seismometer seismic stations. Coda wave envelopes of the filtered seismic traces were fitted to the energy transport equation in the diffusion approximation, obtaining a couple of separate Qi and Qs in six frequency bands. Using numerically estimated sensitivity kernels for coda waves, separate images of each quality factor were produced. Results appear stable and robust. They show that scattering attenuation prevails over intrinsic attenuation. The scattering pattern shows a strong concordance with the tectonic lineaments in the area, while an area of high total attenuation coincides with the zone where most of the volcanic activity occurs. Our results provide evidence that the most important attenuation effects in volcanic areas are associated with the presence of geological heterogeneities.
    Beschreibung: Published
    Beschreibung: 1717–1724
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Attenuation Tomography ; Seismic scattering ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
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    Unbekannt
    Looking for layered anisotropic structures in the mantle beneath the northern Apennines (2015)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Competing geodynamic scenarios proposed for northern Apennines (Italy) make very different predictions for the orientation of strain in the upper mantle. Constraints on the pattern are offered by observations of seismic anisotropy. Previous study of the anisotropy beneath the northern Apennines used birefringence of core-refracted shear waves (SKS phases), and demonstrated the presence of two domains: Tuscan and Adria. In the transition between the two domains, across the Apennines orogen, anisotropy measurements reflect a complex deep structure. To define better the upper-mantle structure beneath this area we analyze seismological data recorded by a set of seismic stations that operated for 3 years, between 2003 and 2006, located in the outer part of the Apennines belt, in the Adria terrane, collected by the RETREAT Project. Directionally distributed sets of SKS records were inverted for layered anisotropic structures with a well-tested method, adding new results to previous hypotheses for this area. New data analysis argues for two-layer anisotropy for sites located on the Apennines wedge and also one site in the Tuscan terrane. Beneath the wedge an upper layer with nearly north-south fast polarization pervades the lithospheric mantle, while at depth a nearly NW–SE Apennines-parallel direction is present in the lower layer. Beneath Tuscany a shallower NW–SE direction and a deeper E–W one suggest the deeper strain from active slab retreat, with a mantle-wedge circulation (i.e. an east–west corner flow), overlain by an Apennines-parallel fast polarization that could be a remnant of lower-crust deformation.
    Beschreibung: Published
    Beschreibung: 39-51
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Subduction zones ; Seismic anisotropy ; Northern Apennines ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
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    ANNALS OF GEOPHYSICS: AD MAJORA (2015)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Annals of Geophysics (ISSN: 1593-5213; from 2010, 2037-416X) is a bimonthly international journal, which publishes scientific papers in the field of geophysics sensu lato. It derives from Annali di Geofisica (ISSN: 0365-2556), which commenced publication in January 1948 as a quarterly periodical devoted to general geophysics, seismology, Earth magnetism, and atmospheric studies....
    Beschreibung: Published
    Beschreibung: E0191
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: 5T. Sorveglianza sismica e operatività post-terremoto
    Beschreibung: 6T. Sismicità indotta e caratterizzazione sismica dei sistemi naturali
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: 3V. Dinamiche e scenari eruttivi
    Beschreibung: 4V. Vulcani e ambiente
    Beschreibung: 5V. Sorveglianza vulcanica ed emergenze
    Beschreibung: 1A. Geomagnetismo e Paleomagnetismo
    Beschreibung: 2A. Fisica dell'alta atmosfera
    Beschreibung: 3A. Ambiente Marino
    Beschreibung: 4A. Clima e Oceani
    Beschreibung: 5A. Energia e georisorse
    Beschreibung: 6A. Monitoraggio ambientale, sicurezza e territorio
    Beschreibung: 7A. Geofisica di esplorazione
    Beschreibung: 1IT. Reti di monitoraggio e Osservazioni
    Beschreibung: 2IT. Laboratori sperimentali e analitici
    Beschreibung: 3IT. Calcolo scientifico e sistemi informatici
    Beschreibung: 4IT. Banche dati
    Beschreibung: 5IT. Osservazioni satellitari
    Beschreibung: 6IT. Sale operative
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): editorial ; 01. Atmosphere::01.01. Atmosphere::01.01.99. General or miscellaneous ; 01. Atmosphere::01.01. Atmosphere::01.01.01. Composition and Structure ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.03. Pollution ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.05. Radiation ; 01. Atmosphere::01.01. Atmosphere::01.01.06. Thermodynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 01. Atmosphere::01.02. Ionosphere::01.02.01. Ion chemistry and composition ; 01. Atmosphere::01.02. Ionosphere::01.02.02. Dynamics ; 01. Atmosphere::01.02. Ionosphere::01.02.03. Forecasts ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.02. Ionosphere::01.02.05. Wave propagation ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 01. Atmosphere::01.03. Magnetosphere::01.03.99. General or miscellaneous ; 01. Atmosphere::01.03. Magnetosphere::01.03.01. Interplanetary physics ; 01. Atmosphere::01.03. Magnetosphere::01.03.02. Magnetic storms ; 01. Atmosphere::01.03. Magnetosphere::01.03.03. Magnetospheric physics ; 01. Atmosphere::01.03. Magnetosphere::01.03.04. Structure and dynamics ; 01. Atmosphere::01.03. Magnetosphere::01.03.05. Solar variability and solar wind ; 01. Atmosphere::01.03. Magnetosphere::01.03.06. Instruments and techniques ; 02. Cryosphere::02.01. Permafrost::02.01.99. General or miscellaneous ; 02. Cryosphere::02.01. Permafrost::02.01.01. Active layer ; 02. Cryosphere::02.01. Permafrost::02.01.02. Cryobiology ; 02. Cryosphere::02.01. Permafrost::02.01.03. Cryosol ; 02. Cryosphere::02.01. Permafrost::02.01.04. Periglacial processes ; 02. Cryosphere::02.01. Permafrost::02.01.05. Seasonally frozen ground ; 02. Cryosphere::02.01. Permafrost::02.01.06. Thermokarst ; 02. Cryosphere::02.01. Permafrost::02.01.07. Tundra ; 02. Cryosphere::02.01. Permafrost::02.01.08. Instruments and techniques ; 02. Cryosphere::02.02. Glaciers::02.02.99. General or miscellaneous ; 02. Cryosphere::02.02. Glaciers::02.02.01. Avalanches ; 02. Cryosphere::02.02. Glaciers::02.02.02. Cryosphere/atmosphere Interaction ; 02. Cryosphere::02.02. Glaciers::02.02.03. Geomorphology ; 02. Cryosphere::02.02. Glaciers::02.02.04. Ice ; 02. Cryosphere::02.02. Glaciers::02.02.05. Ice dynamics ; 02. Cryosphere::02.02. Glaciers::02.02.06. Mass balance ; 02. Cryosphere::02.02. Glaciers::02.02.07. Ocean/ice interaction ; 02. Cryosphere::02.02. Glaciers::02.02.08. Rock glaciers ; 02. Cryosphere::02.02. Glaciers::02.02.09. Snow ; 02. Cryosphere::02.02. Glaciers::02.02.10. Instruments and techniques ; 02. Cryosphere::02.03. Ice cores::02.03.99. General or miscellaneous ; 02. Cryosphere::02.03. Ice cores::02.03.01. Aerosols ; 02. Cryosphere::02.03. Ice cores::02.03.02. Atmospheric Chemistry ; 02. Cryosphere::02.03. Ice cores::02.03.03. Climate Indicators ; 02. Cryosphere::02.03. Ice cores::02.03.04. Ice Core Air Bubbles ; 02. Cryosphere::02.03. Ice cores::02.03.05. Paleoclimate ; 02. Cryosphere::02.03. Ice cores::02.03.06. Precipitation ; 02. Cryosphere::02.03. Ice cores::02.03.07. Teleconnection ; 02. Cryosphere::02.03. Ice cores::02.03.08. Temperature ; 02. Cryosphere::02.03. Ice cores::02.03.09. Instruments and techniques ; 02. Cryosphere::02.04. Sea ice::02.04.99. General or miscellaneous ; 02. Cryosphere::02.04. Sea ice::02.04.01. Atmosphere/sea ice/ocean interaction ; 02. Cryosphere::02.04. Sea ice::02.04.02. Leads ; 02. Cryosphere::02.04. Sea ice::02.04.03. Polynas ; 02. Cryosphere::02.04. Sea ice::02.04.04. Instruments and techniques ; 03. Hydrosphere::03.01. General::03.01.99. General or miscellaneous ; 03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling ; 03. Hydrosphere::03.01. General::03.01.02. Equatorial and regional oceanography ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 03. Hydrosphere::03.01. General::03.01.04. Ocean data assimilation and reanalysis ; 03. Hydrosphere::03.01. General::03.01.05. Operational oceanography ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology ; 03. Hydrosphere::03.01. General::03.01.07. Physical and biogeochemical interactions ; 03. Hydrosphere::03.01. General::03.01.08. Instruments and techniques ; 03. Hydrosphere::03.02. Hydrology::03.02.99. General or miscellaneous ; 03. Hydrosphere::03.02. Hydrology::03.02.01. Channel networks ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 03. Hydrosphere::03.02. Hydrology::03.02.05. Models and Forecasts ; 03. Hydrosphere::03.02. Hydrology::03.02.06. Water resources ; 03. Hydrosphere::03.02. Hydrology::03.02.07. Instruments and techniques ; 03. Hydrosphere::03.03. Physical::03.03.99. General or miscellaneous ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 03. Hydrosphere::03.03. Physical::03.03.02. General circulation ; 03. Hydrosphere::03.03. Physical::03.03.03. Interannual-to-decadal ocean variability ; 03. Hydrosphere::03.03. Physical::03.03.04. Upper ocean and mixed layer processes ; 03. Hydrosphere::03.03. Physical::03.03.05. Instruments and techniques ; 03. Hydrosphere::03.04. Chemical and biological::03.04.99. General or miscellaneous ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.07. Radioactivity and isotopes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.01. Composition and state ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.03. Heat flow ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.02. Earth rotation ; 04. Solid Earth::04.03. Geodesy::04.03.03. Gravity and isostasy ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.05. Geomagnetism::04.05.99. General or miscellaneous ; 04. Solid Earth::04.05. Geomagnetism::04.05.01. Dynamo theory ; 04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals ; 04. Solid Earth::04.05. Geomagnetism::04.05.03. Global and regional models ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.05. Geomagnetism::04.05.05. Main geomagnetic field ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques ; 04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.01. Continents ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.03. Heat generation and transport ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data ; 05. General::05.02. Data dissemination::05.02.05. Collections ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.04. Instrumentation and techniques of general interest::05.04.99. General or miscellaneous ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous ; 05. General::05.06. Methods::05.06.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.01. Environmental risk ; 05. General::05.08. Risk::05.08.02. Hydrogeological risk ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
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    The 3D Attenuation Structure of Deception Island (Antarctica) (2015)
    Springer Science+Business Media B.V.
    Details
    Publikationsdatum: 2019-03-05
    Beschreibung: The seismic and volcanological structure of Deception Island (Antarctica) is an intense focus topic in Volcano Geophysics. The interpretations given by scientists on the origin, nature, and location of the structures buried under the island strongly diverge. We present a high-resolution 3D P-wave attenuation tomography model obtained by using the coda normalization method on 20,293 high-quality waveforms produced by active sources. The checkerboard and synthetic anomaly tests guarantee the reproduction of the input anomalies under the island down to a depth of 4 km. The results, once compared with our current knowledge on the geological, geochemical, and geophysical structure of the region, depict Deception as a piecemeal caldera structure coming out of the Bransfield Trough. Highattenuation anomalies contouring the northeastern emerged caldera rim correlate with the locations of sediments. In our interpretation, the main attenuation contrast, which appears under the collapsed southeastern caldera rim, is related to the deeper feeding systems. A unique P-wave high-attenuation spherical-like anomaly in the inner bay extends between depths of 1 and 3 km. The northern contour of the anomaly coincides with the calderic rim both at 1 and 2 km, while smaller anomalies connect it with deeper structures below 3 km, dipping toward the Bransfield Trough. In our interpretation, the large upper anomaly is caused by a high-temperature shallow (1–3 km deep) geothermal system, located beneath the sediment-filled bay in the collapsed blocks and heated by smaller, deeper contributions of molten materials (magma) rising from southeast.
    Beschreibung: Published
    Beschreibung: 371–390
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Attenuation ; Scattering ; Tomography ; Antarctica ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 16
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    2010-2014 Seismic activity images the activated fault system in the Pollino area, at the Appennines-Calabrian arc boundary region (2015)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The main goal of this study is to increase the understanding of the physical mechanisms behind the ongoing seismic activity in the Pollino area and its influence on the seismic hazard of the Apennines-Calabrian arc boundary region. The study area, near the Pollino massif, is located at the northernmost edge of the Calabrian Arc, which is the last oceanic subduction segment along the Africa-Eurasian plate. The subduction results from the sinking of the Ionian oceanic plate beneath the Calabrian Arc-Southern Tyrrhenian Sea and is part of the fragmented tectonic boundary between two macro-plates: Africa and Eurasia. The subduction geometry is well-documented by several seismological studies (i.e. Chiarabba et al., 2005), and the lithospheric structure of the area is quietly well known (i.e. Totaro et al., 2014 and Piana Agostinetti and Amato, 2009) Despite the slow N-S convergence between these major plates, the Southern Tyrrhenian Sea is a large basin characterized by E-W extensional tectonic. Since Late Miocene, the Calabrian Arc slab experienced rapid rollback, moving E to SE at a rate of 5-6 cm/yr, which is by far higher than the ~1-2 cm/yr rate of convergence between Africa and Europa (Faccenna et al., 2004). However, during late Pleistocene, rollback and subduction have slowed and is likely proceeding at less than 1 cm/yr (D’Agostino and Selvaggi., 2004). Geodetic measurements show that the Pollino Range is subject to NE-SW anti-apenninic extension. In the region the strain rate field shows a continuous belt of extensional deformation that follows the ridge of the Southern Apennines and extends in the Pollino region. The extension rate appears to decrease from the Southern Apennines to the Calabria- Lucania border region (D’Agostino et al., 2013). This finding indeed reveals that the Pollino region is deforming and accumulating tectonic strain which results in a complex system of normal active faults striking sub-parallel to the Apennines. Two principal normal faults are present in the Italian Database of the Individual Seismogenic Sources DISS version 3.1.1 (DISS Working Group, 2010) in the Pollino area: the Pollino (P) fault and the “Rimendiello-Mormanno” (RM) fault system. The RM fault is an active seismogenic structure it strikes about NNW-SSE and dips toward NE; it has hosted in its northernmost part a M 5.0 earthquake on 9th September 1998. The P fault has similar strike but dips toward SW: it shows no recent seismicity and is hence one of the most prominent seismic gaps in the Italian historical seismic catalogue (Rovida et al., 2011). Paleoseismic studies have shown that the P fault was active in the last ten thousand years and is capable to produce events with magnitude above 6.0. The DISS database reports as debated source also the Piana Perretti fault (Brozzetti et al., 2009). A detailed structural map of the area interested by the seismic sequence shows three fault systems (Brozzetti et al., 2013) consisting of several aligned fault segments that have been active during the Late Pleistocene and are reasonably presently active. The first fault system strikes NW-SE and dips toward SW (including the Piana Perretti fault at the NE edge of the Mercure Basin), the second one has similar strike and NE dip, while the third one strikes about E-W. Earthquakes reported in the historical catalogues for this area are not very strong. Few earthquakes with magnitude probably less than 6 affected the area, including the Mw=5.6 “Mercure” event in 1998 (Brozzetti et al., 2009). The Parametric Catalogue of Italian earthquakes (CPTI11, Rovida et al., 2011), shows very well the lack of strong earthquakes in the region: there is a clear evidence of large earthquakes in the Campania-Basilicata area (M~7.0) and several strong earthquakes in the Sila region and in the whole Calabrian territory. According to the seismic classification of the national territory, the area affected by the 2010-2014 seismic activity have a relatively higher probability to be shaken by a strong acceleration (Gruppo di Lavoro MPS, 2004). Most of the seismic events occurred in areas where the peak ground acceleration having 10% chance of being exceeded in next 50 years is between the values of 0.225 g and 0.275 g.
    Beschreibung: Published
    Beschreibung: Bologna
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Beschreibung: 5T. Sorveglianza sismica e operatività post-terremoto
    Beschreibung: 1IT. Reti di monitoraggio e Osservazioni
    Beschreibung: open
    Schlagwort(e): Seimic Swarm, Pollino, active faults, Vp/Vs Seismic tomography, seismic anisotropy, temporary seismic network ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Oral presentation
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  • 17
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    Rayleigh wave dispersion measurements reveal low-velocity zones beneath the new crust in the Gulf of California (2015)
    American Geophysical Union
    Details
    Publikationsdatum: 2022-06-14
    Beschreibung: Rayleigh wave tomography provides images of the shallow mantle shear wave velocity structure beneath the Gulf of California. Low-velocity zones (LVZs) are found on axis between 26 and 50 km depth beneath the Guaymas Basin but mostly off axis under the other rift basins, with the largest feature underlying the Ballenas Transform Fault. We interpret the broadly distributed LVZs as regions of partial melting in a solid mantle matrix. The pathway for melt migration and focusing is more complex than an axis-centered source aligned above a deeper region of mantle melt and likely reflects the magmatic evolution of rift segments. We also consider the existence of solid lower continental crust in the Gulf north of the Guaymas Basin, where the association of the LVZs with asthenospheric upwelling suggests lateral flow assisted by a heat source. These results provide key constraints for numerical models of mantle upwelling and melt focusing in this young oblique rift.
    Beschreibung: Published
    Beschreibung: 1766–1774
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Low velocities in the Gulf upper mantle are interpreted as partial melting ; Partial melting under the Guaymas Basin and off axis of the other rift basins ; Lower crustal flow assisted by heat source in N Gulf near mantle upwelling ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 18
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    Deep structure and tectonics of the northern-central Apennines as seen by regional-scale tomography and 3-D located earthquakes (2014)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In this study we present new high-resolution, regional-scale, Vp and Vp/Vs models of the northern-central Apennines along with accurate 3-D locations of a large set of local earthquakes. The main velocity anomalies are consistent with the surface geology in the shallow layers and present evidence for fluids stored within the basement at greater depths beneath the extensional belt. The Adria and Tyrrhenian mantle are defined by positive velocity anomalies below 30 km depth, while a low-Vp, high-Vp/Vs region in between indicates the existence of a hydrated wedge. The results yield new constraints on active processes in the Apennines and more generally envisage the evolution of a postcollisional belt. Velocity anomalies and earthquakes are consistent with a complex system of delamination and sinking of the Adria continental lithosphere, with the peeling of the crust identified by intermediate-depth seismicity. Change of seismicity and structural patterns along the belt indicates that this tectonic process is diachronous and that fluids, released by sunken lithosphere, are stored within the crust, conditioning the occurrence of seismicity and the onset of extension.
    Beschreibung: Published
    Beschreibung: 5391-5403
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Local earthquake tomography ; tectonic of Apennines ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 19
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    The Campi Flegrei Blind Test: Evaluating the Imaging Capability of Local Earthquake Tomography in a Volcanic Area (2013)
    Hindawi Publishing Corporation
    Details
    Publikationsdatum: 2020-11-30
    Beschreibung: During the 1982–1984 bradyseismic crises in the Campi Flegrei area (Italy), the University of Wisconsin deployed a network of seismological stations to record local earthquakes. In order to analyse the potential of the recorded data in terms of tomographic imaging, a blind test was recently set up and carried out in the framework of a research project. A model representing a hypothetical 3D structure of the area containing the Campi Flegrei caldera was also set up, and a synthetic dataset of time arrivals was in turn computed. The synthetic dataset consists of several thousand P- and S-time arrivals, computed at about fourteen stations. The tomographic inversion was performed by four independent teams using different methods. The teams had no knowledge of either the input velocity model or the earthquake hypocenters used to create the synthetic dataset. The results obtained by the different groups were compared and analysed in light of the true model. This work provides a thorough analysis of the earthquake tomography potential of the dataset recording the seismic activity at Campi Flegrei in the 1982–1984 period. It shows that all the tested earthquake tomography methods provide reliable low-resolution images of the background velocity field of the Campi Flegrei area, but with some differences. However, none of them succeeds in detecting the hypothetical structure details (i.e. with a size smaller than about 1.5–2 km), such as a magmatic chamber 4 km deep and especially the smaller, isolated bodies, which represent possible magmatic chimneys and intrusions.
    Beschreibung: Published
    Beschreibung: Article ID 505286
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: N/A or not JCR
    Beschreibung: restricted
    Schlagwort(e): Campi Flegrei ; Tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
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    Unbekannt
    Spatial distribution of intrinsic and scattering seismic attenuation in active volcanic islands – II: Deception Island images (2013)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In this work, we present regional maps of the inverse intrinsic quality factor (Qi −1), the inverse scattering quality factor (Qs −1) and total inverse quality factor (Qt −1) for the volcanic environment of Deception Island (Antarctica). Our attenuation study is based on diffusion approximation, which permits us to obtain the attenuation coefficients for every single couple source-receiver separately. The data set used in this research is derived from an active seismic experiment using more than 5200 offshore shots (air guns) recorded at 32 onshore seismic stations and four ocean bottom seismometers. To arrive at a regional distribution of these values, we used a new mapping technique based on a Gaussian space probability function. This approach led us to create ‘2-D probabilistic maps’ of values of intrinsic and scattering seismic attenuation. The 2-D tomographic images confirm the existence of a high attenuation body below an inner bay of Deception Island. This structure, previously observed in 2-D and 3-D velocity tomography of the region, is associated with a massive magma reservoir. Magnetotelluric studies reach a similar interpretation of this strong anomaly. Additionally, we observed areas with lower attenuation effects that bear correlation with consolidated structures described in other studies and associated with the crystalline basement of the area. Our calculations of the transport mean-free path and absorption length for intrinsic attenuation gave respective values of ≈950 m and 5 km, which are lower than the values obtained in tectonic regions or volcanic areas such as Tenerife Island. However, as observed in other volcanic regions, our results indicate that scattering effects dominate strongly over the intrinsic attenuation.
    Beschreibung: This work has been partially supported by the Spanish project Ephestos, CGL2011–29499-C02–01, by the EU project EC-FP7 MEDiterranean SUpersite Volcanoes (MED-SUV), by the Basque Government researcher training program BFI09.277 and by the Regional project ‘Grupo de Investigaci´on en Geof´ısica y Sismolog´ıa de la Junta de Andaluc´ıa, RNM104.’ Edoardo del Pezzo was partly supported by DPC-INGV projects UNREST SPEED and V2 (Precursori).
    Beschreibung: Published
    Beschreibung: 1957-1969
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismic attenuation; ; Seismic tomography ; Volcano seismology ; Wave scattering and diffraction ; Wave propagation ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 21
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    New insights on volcanic and tectonic structures of the southern Tyrrhenian (Italy) from marine and land seismic data (2013)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present results from the first crustal seismic tomography for the southern Tyrrhenian area, which includes ocean bottom seismometer (OBS) data and a bathymetry correction. This area comprises Mt. Etna, the Aeolian Islands, and many volcanic seamounts, including the Marsili Seamount. The seismicity distribution in the area depends on the complex interaction between tectonics and volcanism. The 3-D velocity model presented in this study is obtained by the inversion of P wave arrival times from crustal earthquakes. We integrate travel time data recorded by an OBS network (Tyrrhenian Deep Sea Experiment), the SN-1 seafloor observatory, and the land network. Our model shows a high correlation between the P wave anomaly distribution and seismic and volcanic structures. Two main low-velocity anomalies underlie the central Aeolian Islands and Mt. Etna. The two volumes, which are related to the well-known active volcanism, are separated and located at different depths. This finding, in agreement with structural, petrography, and GPS data from literature, confirms the independence of the two systems. The strongest negative anomaly is found below Mt. Etna at the base of the crust, and we associate it with the deep feeding system of the volcano. We infer that most of the seismicity is generated in brittle rock volumes that are affected by the action of hot fluids under high pressure due to the active volcanism in the area. Lateral changes of velocity are related to a transition from the western to the central Aeolian Islands and to the passage from continental crust to the Tyrrhenian oceanic uppermost mantle.
    Beschreibung: Published
    Beschreibung: 3703–3719
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): ocean bottom seismometers ; southern Tyrrhenian Sea ; seismic tomography ; Aeolian Islands ; Etna ; oceanic continental crust ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 22
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    Inside Mt. Vesuvius: a new method to look at the seismic (velocity and attenuation) tomographic imaging (2013)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Mt. Vesuvius have been obtained using the programming facilities as well as the enhanced graphical power of Mathematica8TM. The velocity and attenuation space distributions, already calculated inverting respectively P-wave travel times and amplitude spectra of local VT quakes, are first optimally interpolated and then graphically represented in a new Mathematica8TM code notebook (a powerful computational document with more facilities than a simple code) developed by the present authors. The notebook aims at interactively and friendly representing 3D volume distributions of velocity and attenuation parameters. The user can easily obtain vertical sections (N-S, E-W, NE-SW and NW-SE oriented) and define color scales to represent velocity or attenuation variations or prefer iso-surface plots to represent the pattern of peculiar geological structures. The use of dynamic graphical representation, allowing the sliding of any (horizontal and/or vertical) slice through the volume under study, gives an unusual and powerful vision of any small velocity or attenuation anomaly. The (open source) code, coupled with the friendly use of internal routines of Mathematica, allows to adapt the graphical representation to any user necessity. The method appears to be particularly adapt to represent attenuation images, where the space variations of the parameters are strong with respect to their average. The 3-D plots of the interpolated velocity and attenuation fields enhance the image of Mt. Vesuvius structure, evidencing low-velocity associated with high attenuation anomalies which appeared unfocused in the plots reported by Scarpa et al. [2002] and De Siena et al. [2009].
    Beschreibung: Hypocentral locations are taken from GEOVES DataBase (Istituto Nazionale di Geofisica e Vulcanologia - INGV, Osservatorio Vesuviano). Raw data from tomography studies were released by their authors. The software described in this paper has been prepared in the framework of the projects: V2-“Precursori di Eruzioni in Vulcani Quiescenti: Campi Flegrei e Vulcano”. Convenzione INGV-DPC (2012-2013); EPHESTOS CGL2011-2949- C02-01 (University of Granada, Instituto Andaluz de Geofísica); MEDiterranean SUpersite Volcanoes (MED-SUV) FP7 ENV.2012. 6.4-2 Grant agreement no. 308665. (European Community).
    Beschreibung: Published
    Beschreibung: S0443
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Tomography, ; Mt. Vesuvius ; Seismic attenuation ; Mathematica ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
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    Unbekannt
    Monitoraggio sismico del territorio nazionale: stato dell'arte e sviluppo delle reti di monitoraggio sismico (2013)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: Il sistema CUMAS (Cabled Underwater Module for Acquisition of Seismological data) è un prodotto tecnologico-scientifico complesso nato con il Progetto V4 [Iannaccone et al., 2008] allo scopo di monitorare l’area vulcanica dei Campi Flegrei (fenomeno del bradisismo). Si tratta di un modulo sottomarino cablato e connesso a una boa galleggiante (meda elastica). Il sistema è in grado di acquisire e trasmettere alla sala di monitoraggio dell’OV, in continuo e in tempo reale, sia i segnali sismologici sia quelli di interesse geofisico ed oceanografico (maree, correnti marine, segnali acustici subacquei, parametri funzionali di varia natura). Il sistema è in grado di ricevere comandi da remoto per variare diversi parametri di acquisizione e di monitorare un cospicuo numero di variabili di funzionamento. Il sistema si avvale del supporto di una boa galleggiante attrezzata. La boa è installata a largo del golfo di Pozzuoli (Napoli) a circa 3 km dalla costa. Il modulo sottomarino, collegato via cavo alla parte fuori acqua della boa, è installato sul fondale marino a una profondità di circa 100 metri.
    Beschreibung: Submitted
    Beschreibung: 82-85
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 1.8. Osservazioni di geofisica ambientale
    Beschreibung: 2.5. Laboratorio per lo sviluppo di sistemi di rilevamento sottomarini
    Beschreibung: 5.2. TTC - Banche dati di sismologia strumentale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Monitoraggio sismico; sistemi sottomarini; boa; meda elastica ; 01. Atmosphere::01.01. Atmosphere::01.01.99. General or miscellaneous ; 01. Atmosphere::01.01. Atmosphere::01.01.01. Composition and Structure ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.03. Pollution ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.05. Radiation ; 01. Atmosphere::01.01. Atmosphere::01.01.06. Thermodynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.99. General or miscellaneous ; 01. Atmosphere::01.02. Ionosphere::01.02.01. Ion chemistry and composition ; 01. Atmosphere::01.02. Ionosphere::01.02.02. Dynamics ; 01. Atmosphere::01.02. Ionosphere::01.02.03. Forecasts ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.02. Ionosphere::01.02.05. Wave propagation ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations ; 01. Atmosphere::01.03. Magnetosphere::01.03.99. General or miscellaneous ; 01. Atmosphere::01.03. Magnetosphere::01.03.01. Interplanetary physics ; 01. Atmosphere::01.03. Magnetosphere::01.03.02. Magnetic storms ; 01. Atmosphere::01.03. Magnetosphere::01.03.03. Magnetospheric physics ; 01. Atmosphere::01.03. Magnetosphere::01.03.04. Structure and dynamics ; 01. Atmosphere::01.03. Magnetosphere::01.03.05. Solar variability and solar wind ; 01. Atmosphere::01.03. Magnetosphere::01.03.06. Instruments and techniques ; 02. Cryosphere::02.01. Permafrost::02.01.99. General or miscellaneous ; 02. Cryosphere::02.01. Permafrost::02.01.01. Active layer ; 02. Cryosphere::02.01. Permafrost::02.01.02. Cryobiology ; 02. Cryosphere::02.01. Permafrost::02.01.03. Cryosol ; 02. Cryosphere::02.01. Permafrost::02.01.04. Periglacial processes ; 02. Cryosphere::02.01. Permafrost::02.01.05. Seasonally frozen ground ; 02. Cryosphere::02.01. Permafrost::02.01.06. Thermokarst ; 02. Cryosphere::02.01. Permafrost::02.01.07. Tundra ; 02. Cryosphere::02.01. Permafrost::02.01.08. Instruments and techniques ; 02. Cryosphere::02.02. Glaciers::02.02.99. General or miscellaneous ; 02. Cryosphere::02.02. Glaciers::02.02.01. Avalanches ; 02. Cryosphere::02.02. Glaciers::02.02.02. Cryosphere/atmosphere Interaction ; 02. Cryosphere::02.02. Glaciers::02.02.03. Geomorphology ; 02. Cryosphere::02.02. Glaciers::02.02.04. Ice ; 02. Cryosphere::02.02. Glaciers::02.02.05. Ice dynamics ; 02. Cryosphere::02.02. Glaciers::02.02.06. Mass balance ; 02. Cryosphere::02.02. Glaciers::02.02.07. Ocean/ice interaction ; 02. Cryosphere::02.02. Glaciers::02.02.08. Rock glaciers ; 02. Cryosphere::02.02. Glaciers::02.02.09. Snow ; 02. Cryosphere::02.02. Glaciers::02.02.10. Instruments and techniques ; 02. Cryosphere::02.03. Ice cores::02.03.99. General or miscellaneous ; 02. Cryosphere::02.03. Ice cores::02.03.01. Aerosols ; 02. Cryosphere::02.03. Ice cores::02.03.02. Atmospheric Chemistry ; 02. Cryosphere::02.03. Ice cores::02.03.03. Climate Indicators ; 02. Cryosphere::02.03. Ice cores::02.03.04. Ice Core Air Bubbles ; 02. Cryosphere::02.03. Ice cores::02.03.05. Paleoclimate ; 02. Cryosphere::02.03. Ice cores::02.03.06. Precipitation ; 02. Cryosphere::02.03. Ice cores::02.03.07. Teleconnection ; 02. Cryosphere::02.03. Ice cores::02.03.08. Temperature ; 02. Cryosphere::02.03. Ice cores::02.03.09. Instruments and techniques ; 02. Cryosphere::02.04. Sea ice::02.04.99. General or miscellaneous ; 02. Cryosphere::02.04. Sea ice::02.04.01. Atmosphere/sea ice/ocean interaction ; 02. Cryosphere::02.04. Sea ice::02.04.02. Leads ; 02. Cryosphere::02.04. Sea ice::02.04.03. Polynas ; 02. Cryosphere::02.04. Sea ice::02.04.04. Instruments and techniques ; 03. Hydrosphere::03.01. General::03.01.99. General or miscellaneous ; 03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling ; 03. Hydrosphere::03.01. General::03.01.02. Equatorial and regional oceanography ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 03. Hydrosphere::03.01. General::03.01.04. Ocean data assimilation and reanalysis ; 03. Hydrosphere::03.01. General::03.01.05. Operational oceanography ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology ; 03. Hydrosphere::03.01. General::03.01.07. Physical and biogeochemical interactions ; 03. Hydrosphere::03.01. General::03.01.08. Instruments and techniques ; 03. Hydrosphere::03.02. Hydrology::03.02.99. General or miscellaneous ; 03. Hydrosphere::03.02. Hydrology::03.02.01. Channel networks ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 03. Hydrosphere::03.02. Hydrology::03.02.05. Models and Forecasts ; 03. Hydrosphere::03.02. Hydrology::03.02.06. Water resources ; 03. Hydrosphere::03.02. Hydrology::03.02.07. Instruments and techniques ; 03. Hydrosphere::03.03. Physical::03.03.99. General or miscellaneous ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 03. Hydrosphere::03.03. Physical::03.03.02. General circulation ; 03. Hydrosphere::03.03. Physical::03.03.03. Interannual-to-decadal ocean variability ; 03. Hydrosphere::03.03. Physical::03.03.04. Upper ocean and mixed layer processes ; 03. Hydrosphere::03.03. Physical::03.03.05. Instruments and techniques ; 03. Hydrosphere::03.04. Chemical and biological::03.04.99. General or miscellaneous ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.07. Radioactivity and isotopes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.01. Composition and state ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.03. Heat flow ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.02. Earth rotation ; 04. Solid Earth::04.03. Geodesy::04.03.03. Gravity and isostasy ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.05. Geomagnetism::04.05.99. General or miscellaneous ; 04. Solid Earth::04.05. Geomagnetism::04.05.01. Dynamo theory ; 04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals ; 04. Solid Earth::04.05. Geomagnetism::04.05.03. Global and regional models ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.05. Geomagnetism::04.05.05. Main geomagnetic field ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques ; 04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.01. Continents ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.03. Heat generation and transport ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data ; 05. General::05.02. Data dissemination::05.02.05. Collections ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.04. Instrumentation and techniques of general interest::05.04.99. General or miscellaneous ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous ; 05. General::05.06. Methods::05.06.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction ; 05. General::05.07. Space and Planetary sciences::05.07.02. Space weather ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.01. Environmental risk ; 05. General::05.08. Risk::05.08.02. Hydrogeological risk ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 24
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    Accompanying material of a paper (2013)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: KFUPM - Grant n. RG1115-1
    Beschreibung: Submitted
    Beschreibung: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Beschreibung: open
    Schlagwort(e): 3D relocation ; 3D tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: web product
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  • 25
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    The attenuation mechanism of S-waves in the source zone of the 1999 Chamoli earthquake (2013)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In the present study the attenuation mechanism of seismic wave energy in and around the source area of the Chamoli earthquake of 29th March 1999 is estimated using the aftershock data. Most of the analyzed events are from the vicinity of the Main Central Thrust (MCT), which is a well-defined tectonic discontinuity in the Himalayas. Separation of intrinsic (Q 1 i ) and scattering (Q 1 s ) attenuation coefficient is done over the frequencies 1, 2, 4, 8 and 16 Hz using Multiple Lapse Time Window Analysis (MLTWA) method. It is observed that S-waves and their coda are primarily attenuated due to scattering attenuation and seismic albedo is very high at all the frequencies. A comparison of attenuation characteristics obtained using these aftershock data with those obtained using data of general seismicity of this region reveal that at lower frequencies both intrinsic and scattering attenuation for Chamoli was much higher compared to those for Garwhal-Kumaun region using general seismicity data. At higher frequencies intrinsic attenuation for Chamoli is lower than and scattering attenuation is comparable to those obtained using general seismicity data of Garwhal-Kumaun region.
    Beschreibung: A partial support has been given by Italy INGV-DPC (Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento di Protezione Civile) Projects UNREST and SPEED, and by Italy’s Ministry of Education PRIN project (Seismic Hazard in Central Apennines, UR Del Pezzo).
    Beschreibung: Published
    Beschreibung: 446-454
    Beschreibung: 1T. Geodinamica e interno della Terra
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): MLTWA ; Intrinsic attenuation ; Scattering attenuation ; Chamoli Himalayas ; Himalayas ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 26
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    Spatial distribution of intrinsic and scattering seismic attenuation in active volcanic islands – I: model and the case of Tenerife Island (2013)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The complex volcanic system of Tenerife Island is known to have a highly heterogeneous character, as recently confirmed by velocity tomography.We present new information derived from intrinsic quality factor inverse maps (Qi −1), scattering quality factor inverse maps (Qs −1) and total quality factor inverse maps (Qt −1) obtained for the same region. The data set used in this work is the result of the analysis of an active seismic experiment carried out, using offshore shots (air guns) recorded at over 85 onshore seismic stations. The estimates of the attenuation parameters are based on the assumption that the seismogram energy envelopes are determined by seismic energy diffusion processes occurring inside the island. Diffusion model parameters, proportional to Qi −1 and to Qs −1, are estimated from the inversion of the energy envelopes for any source–receiver couple. They are then weighted with a new graphical approach based on a Gaussian space probability function, which allowed us to create ‘2-D probabilistic maps’ representing the space distribution of the attenuation parameters. The 2-D images obtained reveal the existence of a zone in the centre of the island characterized by the lowest attenuation effects. This effect is interpreted as highly rigid and cooled rocks. This low-attenuation region is bordered by zones of high attenuation, associated with the recent historical volcanic activity. We calculate the transport mean free path obtaining a value of around 4 km for the frequency range 6–12 Hz. This result is two orders of magnitude smaller than values calculated for the crust of the Earth. An absorption length between 10 and 14 km is associated with the average intrinsic attenuation parameter. These values, while small in the context of tectonic regions, are greater than those obtained in volcanic regions such as Vesuvius or Merapi. Such differences may be explained by the magnitude of the region of study, over three times larger than the aforementioned study areas. This also implies deeper sampling of the crust, which is evidenced by a change in the values of seismic attenuation. One important observation is that scattering attenuation dominates over the intrinsic effects, Qi being at least twice the value of Qs.
    Beschreibung: This work has been partially supported by the Spanish project Ephestos, CGL2011-29499-C02-01, by the EU project EC-FP7 MEDiterranean SUpersite Volcanoes (MED-SUV), by the Basque Government researcher training program BFI09.277 and by the Regional project ‘Grupo de Investigaci´on en Geof´ısica y Sismolog´ıa de la Junta de Andaluc´ıa, RNM104’. EdP has been partly supported by DPC-INGV projects UNREST SPEED and V2 (Precursori).
    Beschreibung: Published
    Beschreibung: 1942-1956
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismic attenuation ; ; Seismic tomography; ; Volcano seismology ; Wave propagation. ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 27
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    Hints on the deformation penetration induced by subductions and collision processes: Seismic anisotropy beneath the Adria region (Central Mediterranean) (2013)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Adria is a small region surrounded by three mountain belts: the Alps, the Apennines, and the Dinarides, built up by long evolution of subduction and collisional systems. We present 253 shear wave splitting measurements obtained by studying more than 100 teleseismic events for 12 stations. SKS splitting measurements show 3-D complexity and quite strong upper mantle deformation. We carefully analyzed results in terms of back azimuthal coverage and interpret measurements as related to Adria rotation and to subductions evolution. In the northern part of Adria, the anisotropy pattern follows the arcuate shape of the Alps; the same pattern, parallel to the mountains, occurs along the Apennines, but fast directions show a sudden change in the Adria foreland. This lateral variation has been analyzed to isolate a distinct Adria mantle anisotropic pattern, which is identified as NE-SW fast direction along the western microplate boundary and as N-S fast direction at Trieste. This pattern might be induced by drag effect of the counterclockwise rotation of Adria lithosphere that behaves as an independent microplate as identified by GPS data. Our measurements suggest that the geodynamic process that generated the Alps is more efficient deforming a larger volume of mantle than its Apennine counterpart. Moreover, the mantle circulation we hypothesize looking at the regional-scale patterns of anisotropy requires the existence of an escape route beneath the Alps-Apennines transition, through which the mantle flows and feed circulation in the Tyrrhenian mantle system as suggested by previous geodynamic models and as seen by some tomographic studies.
    Beschreibung: Published
    Beschreibung: 5814–5826
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismic Anisotropy ; Adriatic region ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
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    New insights from seismic tomography on the complex geodynamic evolution of two adjacent domains: Gulf of Cadiz and Alboran Sea (2013)
    American Geophysical Union
    Details
    Publikationsdatum: 2021-11-09
    Beschreibung: In this study, we present a three-dimensional P wave upper-mantle tomography model of the southwest Iberian margin and Alboran Sea based on teleseismic arrival times recorded by Iberian and Moroccan land stations and by a seafloor network deployed for 1 year in the Gulf of Cadiz area during the European Commission Integrated observations from NEAR shore sourcES of Tsunamis: towards an early warning system (EC NEAREST) project. The three-dimensional model was computed down to 600 kmdepth. The tomographic images exhibit significant velocity contrasts, as large as 3%, confirming the complex evolution of this plate boundary region. Prominent high-velocity anomalies are found beneath Betics-Alboran Sea, off-shore southwest Portugal, and north Portugal, at sublithospheric depths. The transition zones between high- and low-velocity anomalies in southwest and south Iberia are associated to the contact of oceanic and continental lithosphere. The fast structure below the Alboran Sea-Granada area depicts an L-shaped body steeply dipping from the uppermost mantle to the transition zone where it becomes less curved. This anomaly is consistent with the results of previous tomographic investigations and recent geophysical data such as stress distribution, GPS measurements of plate motion, and anisotropy patterns. In the Atlantic domain, under the Horseshoe Abyssal Plain, the main feature is a high-velocity zone found at uppermost mantle depths. This feature appears laterally separated from the positive anomaly recovered in the Alboran domain by the interposition of low-velocity zones which characterize the lithosphere beneath the southwest Iberian peninsula margin, suggesting that there is no continuity between the high-velocity anomalies of the two domains west and east of the Gibraltar Strait.
    Beschreibung: Published
    Beschreibung: 1587–1601
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Upper-mantle seismic tomography ; land and marine seismic networks ; SW Iberian margin ; Alboran Sea ; Atlantic domain ; Gulf of Cadiz ; 03. Hydrosphere::03.01. General::03.01.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
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    Reference seismic velocity Earth model for Italy from local source tomography and 30 years of controlled source seismology data (2012)
    Details
    Publikationsdatum: 2020-10-26
    Beschreibung: We present here a new high resolution regional P-wave velocity model for the lithosphere beneath the Italian region obtained by including information on the Moho topography, and integrating results from local earthquake tomography with 30 years of CSS data, applying the method of Waldhauser (1996). For the 3D moho map, we extended the crustal model, already available for the Alps by Lippitsch et al., 2003, to the Italian peninsula, Corsica, Sardinia, and Sicily. The tomographic model is obtained by inverting 166,000 Pg and Pn arrival times large part of which have been automatically picked and consistently weighted with an advanced automatic picking system (Aldersons, 2004). The resolution of the obtained velocity model is consistently higher and the grid spacing consistently smaller than in previous tomographic works targeting the same region. We are able to image the complex geometry of this part of the subduction-collision system between the Eurasian and African plates adding important details to the overview derived by the teleseismic tomography. Our results clearly show the plate boundary at Moho level from the Alps to the Southern Apennines and the Calabrian Arc in a volume unresolved in previous studies. The use of global 1D velocity models based on the flat Earth assumption is a pre-requisite to refine and interpret images and seismic responses of the earth obtained with geophysical studies (P and S tomography, surface wave tomography etc). Our model is suitable as a good starting point for a 3D velocity reference model of the crust and upper mantle beneath the Mediterranean area to be extended to the Adriatic Sea and to the Ionian Sea, with benefit for earthquakes location,teleseismic tomography, focal mechanisms and CMT
    Beschreibung: Published
    Beschreibung: Vienna
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): local earthquake tomography ; velocity model ; Italian Peninsula ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Crustal fracturing and presence of fluid as revealed by seismic anisotropy: Case histories from seismogenic areas in the Apennines (Italy) (2012)
    Details
    Publikationsdatum: 2020-12-17
    Beschreibung: An automatic analysis code, Anisomat+, was developed, tested and improved to calculate anisotropic parameters: fast polarization direction and delay time. Anisomat+ was applied on data coming from three zones of the Apennines in Italy. For each area, anisotropic parameters have been interpreted to determine the fracture and stress field taking into account the geological and structural settings. It was recognized that average of fast directions are oriented NW-SE at all sites, in agreement with the orientation of maximum horizontal stress and also with the strike of the main fault structures. The mean values of normalized delay time range from 0.005 s/km to 0.007 s/km and to 0.009 s/km, respectively for L'Aquila region, Alto Tiberina Fault area and Val D'Agri basin, suggesting a 3-4% of crustal anisotropy. Moreover, for each area, the spatial distributions of anisotropic parameters are examined, for L’Aquila 2009 seismic sequence also their temporal distribution is discussed.
    Beschreibung: Published
    Beschreibung: 417-433
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): seismic anisotropy ; Earth Crust ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Evidence for the contemporary magmatic system beneath Long Valley Caldera from local earthquake tomography and receiver function analysis (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present a new P wave and S wave velocity model for the upper crust beneath Long Valley Caldera obtained using local earthquake tomography and receiver function analysis. We computed the tomographic model using both a graded inversion scheme and a traditional approach. We complement the tomographic Vp model with a teleseismic receiver function model based on data from broadband seismic stations (MLAC and MKV) located on the SE and SW margins of the resurgent dome inside the caldera. The inversions resolve (1) a shallow, high‐velocity P wave anomaly associated with the structural uplift of a resurgent dome; (2) an elongated, WNW striking low‐velocity anomaly (8%–10 % reduction in Vp) at a depth of 6 km (4 km below mean sea level) beneath the southern section of the resurgent dome; and (3) a broad, low‐velocity volume (∼5% reduction in Vp and as much as 40% reduction in Vs) in the depth interval 8–14 km (6–12 km below mean sea level) beneath the central section of the caldera. The two low‐velocity volumes partially overlap the geodetically inferred inflation sources that drove uplift of the resurgent dome associated with caldera unrest between 1980 and 2000, and they likely reflect the ascent path for magma or magmatic fluids into the upper crust beneath the caldera.
    Beschreibung: Published
    Beschreibung: B12314
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic Tomography ; Long Valley Caldera ; Receiver Function ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    A Crustal Model for the Eastern Alps Region and a New Moho Map in Southeastern Europe (2012)
    Springer Verlag
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In the last two decades, south-central Europe and the Eastern Alps have been widely explored by many seismic refrac- tion experiments (e.g., CELEBRATION 2000, ALP 2002, SUDETES 2003). Although quite detailed images are available along linear profiles, a comprehensive, three-dimensional crustal model of the region is still missing. This limitation makes this region a weak spot in continental-wide comprehensive represen- tations of crustal structure. To improve on this situation, we select and collect 37 published active-source seismic lines in this region. After geo-referencing each line, we sample them along vertical profiles—every 50 km or less along the line—and derive P-wave velocities in a stack of homogeneous layers (separated by discon- tinuities: depth of crystalline basement, top of lower crust, and Moho). We finally merge the information using geostatistical methods, and infer S-wave velocity and density using empirical scaling relations. We present here the resulting crustal model for a region encompassing the Eastern Alps, Dinarides, Pannonian basin, Western Carpathians and Bohemian Massif, covering the region within 45º-51ºN and 11º-22ºE with a resolution of 0.2ºx0.2º. We are also able to extend and update the map of Moho depth in a wider region within 35^-51^N and 12^-45^E; gathering Moho values from the collected seismic lines, other published dataset and using the European plate reference EPcrust as a background. All the digitized profiles and the resulting model are available online.
    Beschreibung: Published
    Beschreibung: 1575-1588
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Crustal model ; crust ; Moho depth ; Europe ; Eastern Alps ; kriging ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Images of the Iberian lithosphere from one local earthquake (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: On 12 August 2007, a magnitude Mw 4.7 intraplate earthquake occurred near the center of the Iberian Peninsula, an area characterized by comparably simple crustal structure within the complex Iberia–Maghreb plate boundary zone, and characterized by complete azimuthal coverage with seismic broadband stations. We analyze regional intermediate-period (20- to 50-s) coda waveforms for this earth- quake. They contain energy representing late-arriving surface waves that have been reflected laterally at lithospheric heterogeneities in or around Iberia, but complexity of the coda waveforms hampers a direct interpretation. We use coda recordings as the source for a back-propagating adjoint wave field and compute 3D Born sensitivity kernels for the dependence of least-squares waveform misfits of coda waves on wave speed variations. We hereby image the origin of single scattering recorded in the coda. Misfit kernels for P- and S-wave velocity show azimuth-dependent intensity variation as a result of source radiation, and an appropriate compensation significantly improves imaging quality, thereby revealing several clear lineaments. These are interpreted as surface-wave reflectors due to deep-rooted heterogeneity such as terrain boundaries or Moho topography, demonstrating the ability of the approach to unravel complex waveforms, and providing a new point of view on regional lithospheric structure.
    Beschreibung: Published
    Beschreibung: 881-887
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): tomography ; computational seismology ; wave scattering and diffraction ; crustal structure ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 34
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    Seismic anisotropy and subduction in Southern Italy (2012)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In the current work we present a large collection of shear wave splitting measurements in the Calabrian Arc-Tyrrhenian basin subduction system. For our analysis we used earthquakes recorded from 2003 to 2005 at the CAT/SCAN temporary network and at the INGV national network. The dataset consists of SKS teleseismic phases (earthquakes with delta 87° - 112° and magnitude greater than 6.0) and of local S phases (events deeper than 150 km). We used the method of Silver and Chan to obtain the splitting parameters: fast direction (φ) and delay time (δt). Shear wave splitting results reveal the presence of a strong seismic anisotropy with a complex pattern of fast directions in the subduction system below the region. The SKS fast polarization directions define three anisotropic domains which correspond to the three different geological and geodynamic regions: the Calabrian Arc domain with fast directions oriented NNE-SSW;the Southern Apennines domain with fast directions oriented NNW-SSE and the Apulian Platform domain with fast directions oriented almost N-S in the northern part and ENE-WSW in the southern. The large number of splitting parameters evaluated for events coming from different back-azimuth allow us to hypothesize the presence of a depth dependence anisotropic structure in each of the identified domains and to constrain at 50 km depth the upper limit of the anisotropic layer. We interpret the trench-parallel φ observed in Calabrian Arc and in Southern Apennines as a mantle flow below the slab, likely due to the pressure induced by the retrograde motion of the slab itself. The pattern of trench perpendicular φ in the Apulian Platform seems to be not a direct result of the roll-back motion of the slab and may be explained as frozen-in lithospheric anisotropy or as asthenospheric flow deflected by the complicated structure of the Adriatic microplate. Results obtained with S phases show an extremely complex pattern of fast directions and delay times. These last measures are mainly located in the south-eastern sector of the Tyrrhenian Sea in correspondence of the high velocity body imaged at 150 km depth by the tomography. We related this strong fast directions variability inside the slab to the complex structure of the slab itself. The variable pattern of SKS and S splitting measurements suggest the presence of a local scale mantle flow strongly controlled by the geometry and motion of the anisotropic slab.
    Beschreibung: Published
    Beschreibung: Montpellier, France
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): Seismic anisotropy ; SKS shear wave splitting ; subduction zones ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
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    Project S1: Analysis of the seismic potential in Italy for the evaluation of the seismic hazard (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: The project S1 was aimed at (a) collecting new data and to update the existing databases needed to quantify seismic hazard; (b) promoting new studies on specific fields of knowledge and less-explored areas of Italy; (c) testing new approaches to evaluate seismic potential; (d) bounding slip rate values to use within probabilistic hazard estimates; and (e) preparing the way towards a future seismic hazard map of Italy. It was designed with three scientific parts – nationwide basic data, rheology, and field studies – and implemented into four tasks: 1) earthquake geodesy and modeling, 2) seismological data and earthquake statistics, 3) earthquake geology, and 4) tsunamis. Although with many difficulties and some delay, described in the appropriate section, all the above objectives have generally been accomplished. New observations were collected through original fieldwork and more sophisticated analyses were performed on existing data. Datasets needed for the seismic hazard estimates were updated at various levels by reducing both epistemic and aleatory uncertainties. New studies were carried out on specific fields of knowledge, e.g. addressing the repeatability of geodetic and stress data measurements or the seismogenic behavior of misoriented faults. Studies on less-explored areas were stimulated, and faults, whose seismic potential was not previously accounted for, were mapped and/or parameterized in the Ionian and Adriatic Seas, in Calabria, Sicily and the Southwestern Alps. Independent approaches to evaluate the seismic potential were tested, and a large effort toward homogenization and verifiability was made. The substantial improvements of nationwide datasets and understanding of the tectonic processes in large areas of the country set the basis for a significantly better assessment of seismic hazard.
    Beschreibung: DPC, INGV, CNR
    Beschreibung: Unpublished
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: open
    Schlagwort(e): earthquakes ; seismic hazard ; 03. Hydrosphere::03.02. Hydrology::03.02.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress
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    Anisotropy and seismic attenuation tomography beneath a retreating subduction system: the Southern Tyrrhenian Sea case study (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: The Southern Tyrrhenian subduction system shows a complex interaction among asthenospheric flow, subducting slab and overriding plate. To shed light on the deformations and mechanical properties of the slab and surrounding mantle, we investigated the attenuation and the anisotropic structure through the subduction region. The 3D attenuation results show high-attenuation shallow regions corresponding to the crustal layers, while the slab is imaged as a low-attenuation body bounded by high-attenuation regions located beneath the Aeolian magmatic arc. Between 100-200 km depth, in correspondence of high concentration of earthquakes, the slab is characterized by a spot of high attenuation. Such a feature could be related to the dehydration processes associated to the slab metamorphism. A high-attenuation anomaly is present in the mantle wedge beneath the Aeolian volcanic arc and could indicate mantle melting and slab dehydration and also to the large-scale serpentinization. We also investigated the anisotropic structure of the subduction zone by analyzing shear-wave splitting of the slab earthquakes. Seismic anisotropy reveals a complex pattern of anisotropy across the subduction zone. S-rays sample mainly the slab, showing variable fast directions and delay times. Comparison of S splitting measurements to P-wave velocity anomaly at 100-200 km depth shows that where the rays primarily sample the slab the delay times are small. In contrast, where S rays sample the mantle wedge, the delay times are quite high. This across-subduction variation of delay time depicts the slab as a weakly anisotropic region relative to the mantle above and below and suggests that the main source of anisotropy in the subduction zone is the deformation of the mantle above and below the slab induced by the retrograde motion of the slab.
    Beschreibung: Unpublished
    Beschreibung: Torino
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): subduction zone process ; mantle flow ; slab and mantle wedge anisotropy ; attenuation tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Oral presentation
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  • 37
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    Shear wave splitting in southern tyrrhenian subduction zone (Italy) from CESIS and CAT/SCAN projects (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: In the years 2003 -2006 several broad band stations were installed in Southern Italy: 15 permanent ones (CESIS project), improved the INGV Italian national network and 40 temporary ones were installed in the frame of CAT/SCAN NSF project.We present shear wave splitting measurements obtained analyzing SKS phases and local S phases from slab earthquakes. We used the method of Silver & Chan to obtain shear wave splitting parameters: fast direction and delay time. Shear wave splitting measurements reveals strong seismic anisotropy in the mantle beneath Southern Tyrrhenian subduction system. The SKS splitting results show fast polarization directions varying from NNW-SSE in the Southern Apennines to N-S and to E-SW in Calabria, following the strike of the mountain chain. Moving toward the Adriatic sea the fast directions rotate from N-S to NE-SW. Fast directions could indicate the mantle flow below the slab, due to its retrograde motion but also the lithospheric fabric of the subducting plate. In the Tyrrhenian domain, above the slab, from Sardinia to the Italian and Sicilian coasts the dominant fast direction is E-W and could be related to the opening of the Tyrrhenian basin and to the corner flow in the asthenospheric wedge. In Sicily fast directions depict a ring around the slab edge supporting the existence of a slab tear and of a return flow from the back to the front of the slab. Measurements obtained with intermediate and deep earthquakes slab S phases show an extremely complex pattern of fast directions. They are mostly distributed in front of the Tyrrhenian Calabrian coast in correspondence of the fast velocity anomaly imaged at 150 km depth by tomography. We can relate this fast directions variability to the complex structure of the slab itself. The complex pattern of SKS and S splitting measurements suggests the presence of local scale mantle flow controled by the motion of an anisotropic slab.
    Beschreibung: Published
    Beschreibung: Vienna
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): subduction zone process ; shear wave splitting ; deep seismicity ; Tyrrhenian Sea ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
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  • 38
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    Seismic rays and traveltime tomography of strongly heterogeneous mantle structure: application to the Central Mediterranean (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: The structure of the Earth’s upper mantle near convergent plate margins, such as along the Nubia–Eurasia collision zone in the Mediter ranean, involves strong seismic wave speed contrasts associated with subducting lithospheric slabs and opening backarc basins. In this environment, seismic wave propagation is strongly influenced by heterogeneity, and requires appropriate modelling practice. Although accurate numerical methods are often used to model seismic traveltimes in the crust, only approximate techniques have been used for the mantle, on the assumption that speed contrasts are weaker. We devise, optimize, and test a method aimed at recovering strongly heterogeneous mantle structures using a finite-difference scheme to calculate first-ar rival traveltimes and trace seismic rays with high accuracy even in the presence of strong gradients. We adapt this forward scheme—successfully used in local-scale tomography—to spherical geometry through source-specific Earth flattening approximations, and we split calculations in meshes with different step size to model optimally the crust (with a 2 km step) and the mantle (6 km step). We then use an iterative non-linear inversion approach, starting from a simple 1-D prior model. We test the ability of this procedure to reconstruct sample structures, devised to be illustrative for the Mediter ranean region, using synthetic data calculated on the real distribution of sources and stations reported by the Bulletins of the International Seismological Centre (ISC). Besides regular checkerboard patterns, we also reconstruct a more representative model. Different strategies are used and compared in linear and non-linear inversion. We find that a linear approach, by which rays are only traced once in the background model, may result in an illusory fit to data. Realistic upper-mantle structures strongly deflect seismic rays, and cor rect paths can only be found after a few iterations. Although linear inversion seems able to identify the main features quite well, we verify how non-linear inversion and 3-D ray tracing significantly improve the results, especially when we attempt to reconstruct a realistic structure. We also apply the finite-difference, non-linear, traveltime tomography to data from the ISC to retrieve upper-mantle structure in the Central Mediter ranean. We verify that the non-linear inversion is able to reveal shar pened velocity contrasts and thinner bodies than linear inversion. Clear differentiation found in the non- linear result, between signatures of northern and southern Dinarides—showing lithosphere subducting only beneath the southern sector—is more coherent with the regional geodynamic framework. Such improvements due to non-linear mantle tomography may contribute to the general picture of slab detachment and small-scale mantle convection in the Mediter ranean region, and therefore, significantly impact on geodynamic implications of resulting models.
    Beschreibung: Published
    Beschreibung: 1708–1724
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Body waves ; seismic tomography ; computational seismology ; wave propagation ; Europe ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Seismic anisotropy and attenuation beneath the Southern Italy Subduction zone (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: Subduction zones represent a tectonic region where intense deformations and complex dynamic processes are expected. Although several progress have been made in understanding the structure and the geodynamic evolution of the subduction zones, the active interaction among the subducting slab and the surrounding mantle material remains still debated. The Southern Italy Subduction System is part of the complex tectonic boundary between the Africa-Eurasia macroplates and has been inherited from several phases of fragmentation of the Western Mediterranean subduction zone. It is widely accept that the geodynamic setting of the Southern Italy Subduction System results from the southeast retrograde motion of the northwestward subducting Western Mediterranean slab (i.e. Gueguen et al., 1998; Carminati et al., 1998; Faccenna et al., 2005 and refrences therein). The retrograde motion of the slab was responsible for the creation of the backarc extensional Tyrrhenian Sea and the building of the Southern Apennines and Calabrian arcuate orogenic belts. At present, only the portion of subduction beneath the Calabrian Arc, in the Ionian area, may be active, while a young slab window develops at the Southern Apennines (Lucente et al., 2006). The purpose of this study is to characterize the seismic structure beneath the Southern Italy in order to better define the geometry of the Ionian slab and of the surrounding mantle flows. We therefore analyzed the anisotropic and attenuation properties beneath the study region. Seismic anisotropy is found to be a ubiquitous properties of the Earth due to the mantle deformation and, thus, it is represent a powerful tool to constrain the anisotropic behavior of the upper mantle and of the subducting plate. In particular, the observed anisotropy can help to understand the mantle and the slab deformation and the dynamic processes occurring in the upper-mantle wedge above the sinking oceanic slab and in the mantle below the slab. In this study we present a large collection of shear wave splitting measurements in the Calabrian Arc - Tyrrhenian basin Subduction System. The data analyzed consist of several teleseisms and subduction zone local deep earthquakes (Baccheschi et al., 2007, 2008). We used the method described by Silver and Chan (1991), assuming that shear waves pass through a medium with homogeneous anisotropy and with an horizontal fast axis. We analyzed SKS phases from earthquakes with magnitude greater than 6.0 and epicentral distance Æ° ranging from 87° to 112°. In addition, to obtain the best signal to noise ratio, all teleseisms are band-pass filtered between 0.03-0.3 Hz. The pattern of SKS fast directions, with delay times up to 3.0 s, reveals the existence of a strong seismic anisotropy in the sub-slab mantle region. We observe both trench-parallel and trench-perpendicular fast directions. Fast axes are oriented NE-SW along the Calabrian Arc, parallel to the strike of the subduction. To the N they rotate to NNW-SSE following the curvature of the slab. Fast directions are almost perpendicular to the strike of subduction in front of the slab (Aeolian Islands) and behind the slab (Straits of Messina). In the Apulian domain we observe trench-perpendicular fast directions, oriented N-S and ENEWSW. The pattern of SKS splitting measurements parallel to the strike of the slab suggests that the anisotropy is closely controlled by subduction and by the rollback motion of the slab. These two processes would be responsible for activating mantle flow below and around the slab itself. The pattern of SKS splitting in the Apulian domain seems to be not a direct results of the rollback motion of the slab and may be explained as frozen-in lithospheric anisotropy or as asthenospheric flow deflected by the structure of the Adriatic microplate. In order to obtain a detailed image of the anisotropic structure beneath the Southern Italy Subduction System we also used the direct S waves from earthquake located within the descending Ionian plate. The particular geometry of the Tyrrhenian subduction zone relative to the distribution of the land areas and, consequently, locations of the seismic stations provide an opportunity to collect unique data. In fact, the main massif Calabria is an uplifted fore-arc that lies well trenchward of the volcanic arc. In addition, the slab dips at high angle (about 70°) below Calabria and the lateral extension of the slab is limited and bounded at its edges by the Southern Apennines and Sicily.Seismic stations are distributed in Calabria, in the Southern Apennines and in Sicily and only few are in the Aeolian volcanic arc. This allows most recorded rays to travel through and along the subducted slab. This is not frequently observed worldwide since in most subduction zones, as in Japan, land corresponds to the volcanic arc and trenchward of this the forearc is submerged. This enabled us to sample rays that propagate up the slab and allowed us to separate the different sources of the anisotropy: the subducting lithosphere, the mantle wedge above it and the overriding plate. We analyzed several deep earthquakes, with depth greater tha 150 km, that occurred within the descending slab; S splitting parameters show a complex pattern of anisotropy with variable fast directions across the subduction zone and delay times ranging from 0.1 sec to 2.2 sec. Measurements at single stations are quite variable excluding the overriding plate as main source of anisotropy. The S wave splitting parameters also show frequency-dependent behaviour that we attribute to the presence of small-scale anisotropic heterogeneities. Comparison of the S splitting measurements to the Pwave velocity anomaly at 100-200 km depth shows that where the rays primarily sample the slab the delay times are small. In contrast, where the S rays sample the mantle wedge, the delay times are quite high. This dt pattern depicts the slab as a weakly anisotropic region and suggests that the main source of anisotropy in the subduction zone is the surrounding asthenosphere (Baccheschi et al., submitted to JGR). We also determined the attenuation structure of the slab and of the surrounding regions by the inversion of high quality S-waves t* from slab earthquakes. We obtained high resolution Qs model down to 300 km depth. The results indicate low values of Qs (Qs values down to 200) corresponding to crustal layers (down to 25 km depth), while the slab is characterized by higher but heterogeneous Qs structure (Qs values up to 1100). At 100 km depth the high Qs body is well reconstructed beneath the Calabrian arc and at 200 km depth it is extended offshore the Southern Tyrrhenian Basin beneath the Aeolian Islands. These preliminary attenuation results allowed us to better define the geometry and the boundary of the Ionian slab and distinguish between anisotropy in the slab and in the mantle wedge.
    Beschreibung: Published
    Beschreibung: Prato
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): anisotropy and attenuation tomography ; slab and mantle wedge dynamics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
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  • 40
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    Can local earthquake tomography settle the matter about subduction in the Northern and Central Apennines? Response from a new high resolution P velocity and Vp/Vs ratio 3-D model (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: According to the most common interpretation, the Apennines developed in Neogene and Quaternary times in the hanging wall of a west directed subduction zone. Seismic tomography is the most powerful tool to investigate large volume of Earth at depth, and it has been extensively applied to shed light on the geometry and shape of the subduction under the Italian peninsula. The various experiments were able to display the slab under the Southern Apennines, but even the most recent tomographic images were non-uniquely interpretable and left open questions about the characteristics of the subduction in the Northern-Central sector of the chain. We here present the results of an improved inversion experiment focused on the Northern and Central Apennines. The results do not show any pronounced subduction slab and the most evident anomaly is a low velocity body extending down to 100 km depth, located in a relatively small area under the western Tuscany. On the basis of accurate synthetic tests, we assess that, if established, a subduction like geometry should be visible in our tomographic images. We then conclude that no subduction is imaged in the Northern and Central Apennines. We thus interpret this anomaly as an asthenospheric flow. However, we cannot exclude that our result is due to intrinsic limitations of the methodology. In fact in response to the original question about the capability of local earthquake tomography to settle the matter about subduction, we underline that the absence of deep earthquakes to illuminate the model from below, the existence of seismic gaps in some sectors of the area under study even at shallow depth and the non uniqueness of interpretation of the tomographic images make local tomography unable to give alone definitive information on the deep structure of the Northern and Central Apennines.
    Beschreibung: Published
    Beschreibung: 63-73
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismic tomography ; Apennines ; Subduction ; Asthenospheric upwelling ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
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    Body wave attenuation heralds incoming eruptions at Mount Etna (2012)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: How fast and foreseeable is the magma ascent is one of the most impellent and unanswered issues of volcanology. The velocity of the magma upwelling depends on the local conditions of the volcanic conduit and rheology of the magma (Scandone et al., 2007). During magma emplacement in the shallow crust, transient variations of physical properties underneath active volcanoes are expected and in a few cases observed (Patanè et al., 2006). The predictability of such changes strongly depends on how fast this process is, compared to our ability to handle geophysical data and consistently resolve transient anomalies in the physical properties of the medium. Mt. Etna is a perfect natural laboratory to investigate such issues, due to the almost continuous magmatic activity and the high quality of seismologic and geodetic data. Here we show, for the first time, that seismic attenuation of local earthquakes strongly increases due to the emplacement of magma within the crust, forecasting an incipient eruption at Mt. Etna.
    Beschreibung: Published
    Beschreibung: 503-506
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Attenuation seismic tomography, Mt etna eruptions ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 42
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    Standardization of Seismic Tomographic Models and Earthquake Focal Mechanisms Datasets Based on Web Technologies, Visualization with Keyhole Markup Language (2012)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present two projects in seismology that have been ported to web technologies, which provide results in Keyhole Markup Language (KML) visualization layers. These use the Google Earth geo-browser as the flexible platform that can substitute specialized graphical tools to perform qualitative visual data analyses and comparisons. The Network of Research Infrastructures for European Seismology (NERIES) Tomographic Earth Model Repository contains datasets from over 20 models from the literature. A hierarchical structure of folders that represent the sets of depths for each model is implemented in KML, and this immediately results into an intuitive interface for users to navigate freely and to compare tomographic plots. The KML layer for the European-Mediterranean Regional Centroid-Moment Tensor Catalog displays the focal mechanism solutions or moderate magnitude Earthquakes from 1997 to the present. Our aim in both projects was to also propose standard representations of scientific datasets. Here, the general semantic approach of XML has an important impact that must be further explored, although we find the KML syntax to be more shifted towards detailed visualization aspects. We have thus used, and propose the use of, Javascript Object Notation (JSON), another semantic notation that stems from the web-development community that provides a compact, general-purpose, data-exchange format.
    Beschreibung: Published
    Beschreibung: 47-56
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): seismology ; geophysics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
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    Splitting parameter yield (SPY): A program for semiautomatic analysis of shear wave splitting (2012)
    Elsevier
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: SPY is a Matlab algorithm that analyzes seismic waveforms in a semiautomatic way, providing estimates of the two observables of the anisotropy: the shear-wave splitting parameters. We chose to exploit those computational processes that require less intervention by the user, gaining objectivity and reliability as a result. The algorithm joins the covariance matrix and the cross-correlation techniques, and all the computation steps are interspersed by several automatic checks intended to verify the reliability of the yields. The resulting semiautomation generates two new advantages in the field of anisotropy studies: handling a huge amount of data at the same time, and comparing different yields. From this perspective, SPY has been developed in the Matlab environment, which is widespread, versatile, and user-friendly. Our intention is to provide the scientific community with a new monitoring tool for tracking the temporal variations of the crustal stress field.
    Beschreibung: Published
    Beschreibung: 138-145
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Crustal anisotropy ; Waveform analysis ; Seismic monitoring ; Stress field ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 44
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    Seismic attenuation tomography beneath the retreating Southern Tyrrhenian Sea subduction system (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: We investigate the seismic attenuation structure of the Ionian slab and surrounding mantle beneath the Southern Tyrrhenian subduction system. We present a high-resolution Vp, Vp/Vs, Qp and Qs models obtained by the inversion of high quality P- and S-waves t* from slab earthquakes. In our analysis we first located 304 earthquakes with M〉= 2.8 , depth 〉= 30 km and azimuthal gap 〈= 200 and we used a 3D a priori Vp and Vp/Vs model. Then, t* values were measured from spectra of P and S waves. For computing t* we have determined the corner frequency (fc) which has been estimated using a grid search over the frequency range 1 - 10 Hz using all the recordings for each event. The obtained t* values are then used in the inversion for the 3-D attenuation structure using, and kept fixed, the 3-D velocity model. Tomographic inversion show high-attenuation regions corresponding to the crustal layers with low values of Qs (values down to 200) but high values of Qp. The subducting slab is identified as a body of low attenuation, but heterogeneous in the Qs and Qp structure (Qs values up to 1100; Qp values up to 1200), surrounded by high-attenuation regions beneath the Aeolian magmatic arc. At 100 km depth the high Qp and Qs body is well reconstructed beneath the Calabrian arc and at 200 km depth it is extended offshore the Southern Tyrrhenian Basin beneath the Aeolian Islands. Between 100 and 200 km depth, the Ionian slab is characterized by intermediate depth seismicity, but Qp and Qs models clearly show the existence of high-attenuation region, with low values of Qs and high Qp/Qs structure. The observed low Qp and Qs anomalies could likely due to the fluids released from dehydrating minerals associated to the slab metamorphism. The observed low Qs anomalies regions between the slab and the Aeolian volcanic arc could be indicative of melting processes in the mantle and also of the large-scale serpentinization.
    Beschreibung: Published
    Beschreibung: Vienna
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): seismic attenuation tomography ; slab and mantle wedge fluids release ; subduction zone processes ; Southern Italy ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 45
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    SKS splittings in the southern Apennines-Calabrian arc region (southern Italy) (2012)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: During the years 2003-2006 CAT/SCAN (Calbarian-Apennine-TyrrhenianlSubductionCollision- Accretion Network) temporary broadband stations operate in Southern Apennine and Calabria (Italy). In the same period CESIS-INGV project improved the number of permanent seismic stations in the same area. We analyze the data recorded to study seismic anisotropy and to investigate the mantle flow in the boun(fary-zoile{ between Southern Apennine and Calabriaibeneath and above the subducting slab. In the current work we present new shear wave splittings obtained analyzing SKS phases of 15 teleseisms with epicentral distance ranging from 88.40 to 98.20 and magnitude greater than 6.0. We used the method of Silver & Chan (1991) to obtained anisotropic parameters: delay time and fast polarization direction. The splitting parameters reveal strong seismic anisotropy in the mantle beneath Southern Tyrrhenian Sea- Calabrian Arc System that seems to be controlled by the slab presence. The clear variability in the fast directions allow us to hypothesize the existence of different anisotropic domains: fast polarization directions vary from NNW -SSE in the tyrrhenian side ofthe Southern Apennine to N-S and NE-SW toward the Adriatic Sea. Moving toward the Calabria fast directions are prevalently trench parallel showing a NE-SW orientation following the strike on the mountain chain.
    Beschreibung: Published
    Beschreibung: Chateau of Trest, Czech Republic
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): Seismic anisotropy ; SKS shear wave splitting ; southern Italy subduction system ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 46
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    Parallel ‘large’ dense matrix problems: application to 3D joint inversion of seismological and gravity data (2012)
    Elsevier Science Limited
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: To obtain accurate and reliable estimations of the major lithological properties of the rock within a studied volume, geophysics uses the joint information provided by different geophysical datasets (e.g. gravimetric, magnetic, seismic). Representation of the different types of information entering the problem using probability density functions can provide the mathematical framework to formulate their combination. The maximum likelihood estimator of the resulting joint posterior probability density functions leads to the solution of the problem. However, one key problem appears to limit the use of this solver to an extensive range of real applications: information coming from potential fields that implies the presence of dense matrices in the resolving estimator. It is well known that dense matrix systems rapidly challenge both the algorithms and the computing platforms, and are not suited to high-resolution 3D geophysical analysis. In this study, we propose a procedure that allows us to obtain fast and reliable solutions of the joint posterior probability density functions in the presence of large gravity datasets and using sophisticated model parametrization. As it is particularly CPUconsuming, this 3D problem makes use of parallel computing to improve the performance and the accuracy of the simulations. Analysis of the correctness of the results, and the performance on different parallel environments, shows the portability and the efficiency of the code. This code is applied to a real experiment, where we succeed in recovering a 3D shear-wave velocity and density distribution within the upper mantle of the European continent, satisfying both the seismological and gravity data. On a multiprocessor machine, we have been able to handle forward and inverse calculations with a dense matrix of 215.66 Gb in 18 min, 20 s and 20 min, 54 s, respectively.
    Beschreibung: NERIES INFRAST-2.1-026130, MERG-CT-2007-046522
    Beschreibung: Published
    Beschreibung: 143-156
    Beschreibung: 2.1. TTC - Laboratorio per le reti informatiche, GRID e calcolo avanzato
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Parallel ; Dense matrix ; Block-cyclic distribution ; Inverse problem ; Probability density function ; ScaLAPACK ; Gravity field ; Shear-wave velocity structure ; Density structure ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 47
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    Sequential integrated inversion of tomographic images and gravity data: an application to the Friuli area (Northeastern Italy) (2012)
    Istituto Nazionale di Oceanografia e di Geofisica Sperimentale-OGS
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The three-dimensional pattern of elastic moduli (bulk modulus, Young modulus, shear modulus) of the upper crust (0-10 km depth) has been determined in the Friuli area (north-eastern Italy) from the 3D Vp, Vp/Vs and density structures. Firstly, 3D Pwave velocity and P to S velocity ratio were modeled by joint inversion for hypocentres and velocity structure. Then, we apply the tomographic inversion method of Sequential Integrated Inversion (SII) to recover the three dimensional density structure. The pattern of the elastic moduli is characterized by marked lateral and depth variations that reflect the geologic-structural heterogeneity of the area, produced by the superposition of several tectonic phases with different orientations of the principal axes of stress. The bulk (K), Young (E) and shear (G) moduli image a high rigidity body with an irregular shape, at 4-8 km depth. The body is characterized by G ≥ 3.2·1010 N·m-2, K ≥ 6.8·1010 N·m-2 and E ≥ 8.4·1010 N·m-2 and is associated to platform limestones and dolomitic rocks. The seismicity is mainly located along the sharp variations of the moduli pattern, in or adjacent to high rigidity zones. The most severe earthquakes (ML between 4.5 and 6.4), occurred in the study area from 1976 to the present day, are located in a transition zone from high to low rigidity patterns. Our interpretation is that the elastic moduli variations, closely related to variability in rock mechanical properties, influence the occurrence of earthquakes by processes of stress concentrations. The values of the elastic moduli recently obtained from laboratory measurements on the main lithologic units fall in the middlehigh range of the values obtained with the present investigation. Keywords: Seismic tomography, gravity anomalies, seismicity, elastic moduli, Friuli, NE Italy
    Beschreibung: Published
    Beschreibung: 191-212
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismic tomography ; gravity anomalies ; seismicity ; elastic moduli ; Friuli ; NE Italy ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 48
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    Upper mantle structure below the European continent: Constraints from surface-wave tomography and GRACE satellite gravity data (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We here exploit fundamental mode Rayleigh and Love seismic wave information and the high resolution satellite global gravity model GGM02C to obtain a 1° × 1° 3-D image of: (a) upper-mantle isotropic shear-wave speeds; (b) densities; and (c) density-vS coupling below the European plate (20°N–90°N) (40°W–70°E). The 3-D image of the density-vS coupling provides unprecedented detail of information on the compositional and thermal contributions to density structures. The accurate and high-resolution crustal model allows us to compute a reliable residual topography to understand the dynamic implications of our models. The correlation between residual topography and mantle residual gravity anomalies defines three large-scale regions where upper mantle dynamics produce surface expression: the East European Craton; the eastern side of the Arabian Plate; and the Mediterranean Basin. The effects of mantle convection are also clearly visible at: (1) the Eastern Sirt Embayment; (2) the West African Craton northern margins; (3) the volcanically active region of the Canarian Archipelago; (4) the northern edge of the Central European Volcanic Province; and (5) the Northeastern part of the Atlantic Ocean, between Greenland and Iceland. Strong connections are observed among areas of weak radial anisotropy and areas where the mantle dynamics show surface expression. Although both thermal and additional dependencies have been incorporated into the density model, convective down-welling in the mantle below the East European Craton is required to explain the strong correlation between the estimated negative mantle residual anomalies and the negative residual topography.
    Beschreibung: DATEC MERG-CT-2007-046522 and NERIES INFRAST-2.1-026130
    Beschreibung: Published
    Beschreibung: B09401
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Europe ; GRACE ; density-velocity scaling relationship ; dynamic topography ; surface waves ; upper mantle density ; 04. Solid Earth::04.01. Earth Interior::04.01.01. Composition and state ; 04. Solid Earth::04.03. Geodesy::04.03.03. Gravity and isostasy ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 49
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    Multiresolution Spherical Wavelet Analysis in Global Seismic Tomography (2012)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Every seismic event produces seismic waves which travel throughout the Earth. Seismology is the science of interpreting measurements to derive information about the structure of the Earth. Seismic tomography is the most powerful tool for determination of 3D structure of deep Earth's interiors. Tomographic models obtained at the global and regional scales are an underlying tool for determination of geodynamical state of the Earth, showing evident correlation with other geophysical and geological characteristics. The global tomographic images of the Earth can be written as a linear combinations of basis functions from a specifically chosen set, defining the model parameterization. A number of different parameterizations are commonly seen in literature: seismic velocities in the Earth have been expressed, for example, as combinations of spherical harmonics or by means of the simpler characteristic functions of discrete cells. With this work we are interested to focus our attention on this aspect, evaluating a new type of parameterization, performed by means of wavelet functions. It is known from the classical Fourier theory that a signal can be expressed as the sum of a, possibly infinite, series of sines and cosines. This sum is often referred as a Fourier expansion. The big disadvantage of a Fourier expansion is that it has only frequency resolution and no time resolution. The Wavelet Analysis (or Wavelet Transform) is probably the most recent solution to overcome the shortcomings of Fourier analysis. The fundamental idea behind this innovative analysis is to study signal according to scale. Wavelets, in fact, are mathematical functions that cut up data into different frequency components, and then study each component with resolution matched to its scale, so they are especially useful in the analysis of non stationary process that contains multi-scale features, discontinuities and sharp strike. Wavelets are essentially used in two ways when they are applied in geophysical process or signals studies: 1) as a basis for representation or characterization of process; 2) as an integration kernel for analysis to extract information about the process. These two types of applications of wavelets in geophysical field, are object of study of this work. At the beginning we use the wavelets as basis to represent and resolve the Tomographic Inverse Problem. After a briefly introduction to seismic tomography theory, we assess the power of wavelet analysis in the representation of two different type of synthetic models; then we apply it to real data, obtaining surface wave phase velocity maps and evaluating its abilities by means of comparison with an other type of parametrization (i.e., block parametrization). For the second type of wavelet application we analyze the ability of Continuous Wavelet Transform in the spectral analysis, starting again with some synthetic tests to evaluate its sensibility and capability and then apply the same analysis to real data to obtain Local Correlation Maps between different model at same depth or between different profiles of the same model.
    Beschreibung: Università di Bologna, Alma Mater Studiorum-presso INGV-Bologna.
    Beschreibung: Published
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: open
    Schlagwort(e): Global tomography,surface waves,wavelets ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: thesis
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  • 50
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    EPmantle: a three-dimensional transversely isotropic model of the upper mantle under the European Plate (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: We present a new 3-D transversely isotropic shear wave velocity model of the European and Mediter ranean upper mantle obtained by analysis of surface waves. Data used are fundamental- mode Rayleigh and Love group velocity measurements in the period range 35–170 s, taken on seismograms recorded by European stations for regional earthquakes. The tomographic inversion to map the 3-D earth structure is split into two steps. First, we regionalize the group velocity dispersion measurements, obtaining distinct geographical group velocity maps at different periods; then, each local dispersion curve is inverted separately to find the shear wave velocity structure at depth. The inversion benefits from using a priori information from a 3-D global mantle model (S20RTS) and a new detailed European crustal model (EPcrust) to constrain the shallower layers. The inversion scheme follows a non-linear iterative algorithm by which Rayleigh and Love group slowness are inverted simultaneously for the best-fitting isotropic Voigt shear wave speed and radial anisotropy parameter. Final merging of the vS profiles results in a new higher resolution 3-D model of European upper mantle. We find that Western Europe and Mediter ranean Sea are mainly characterized by relatively low velocities, strongly contrasting with the fast roots of the Eastern European Craton. Many regional scale structures are also evident in the model, thus providing insights into the complex geodynamic framework of the European continent. Most prominent are the low-velocity West Mediter ranean spreading basins and European Cenozoic rift system, and seismically fast features connected to subduction of Adria microplate, Hellenic Arc and Calabrian Arc. Radial anisotropy does not vary very significantly with respect to the PREM profile, as available data only resolve lateral variations to a limited degree due to trade-off with velocity. EPmantle has the potential to provide a reliable seismological reference for the upper-mantle structure in the broad European region.
    Beschreibung: Published
    Beschreibung: 469-484
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Surface waves and free oscillations ; seismic tomography ; Europe. ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 51
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    Seismic structure of the Calabrian subduction zone (2012)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: During the last decades, many studies have been addressing the seismic structure of the crust and upper mantle beneath the Tyrrhenian-Calabrian Arc, crucial to define the deep and shallow geometry of the subducting plate and the circulation of the surrounding mantle. We present the INGV contribution to the understanding of the subduction system from a seismological point of view. We illustrate the most recent results on relocated deep seismicity,on high resolution local earthquake tomography, and on teleseismic tomography with ocean bottom seismometers data. The pattern of mantle flow is imaged by a large collection of shear-wave splitting measurements from national network and temporary deployments. The 3D geometry of the narrow (about 200 km) subducting lithosphere shows a well defined shallow bend from sub-horizontal to 70-75 NW dipping. Lithosphere dives down to 400 km depth and turns again horizontal in the transition zone. Low seismic velocity in the wedge correspond to the Tyrrhenian basin and Aeolian Arc. Focused mantle circulation is induced by the slab motion, with evidences of return flow from behind the subducted lithosphere around the south-western slab edge.
    Beschreibung: Unpublished
    Beschreibung: Rimini
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): geometry of subduction ; circulation of mantle ; deep seismicity ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Oral presentation
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  • 52
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    Subsurface structure of the Solfatara volcano (Campi Flegreicaldera, Italy) as deduced from joint seismic-noise array,volcanological and morphostructural analysis (2012)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The joint application of different seismological techniques for seismic noise analysis, and the results of a volcanological and morphostructural survey, have allowed us to obtain a detailed and well constrained image of the shallow crustal structure of the Solfatara volcano (Campi Flegrei caldera, Italy). Horizontal-to-vertical spectral ratios, inversion of surface wave dispersion curves and polarization analysis provided resonance frequencies and peak amplitudes, shear wave velocity profiles and polarization pattern of coherent ambient noise. These results, combined in a unique framework, indicate that the volcanic edifice is characterized by lateral and vertical discontinuities and heterogeneities in terms of shear wave velocity, lithological contrasts and structural setting. The interpretation of the seismological results, with the volcanological and morphostructural constraints, supports the hypothesis that the volcano has been characterized by a complex and intense activity, with the alternation of constructive and destructive phases, during which magmatic and phreatomagmatic explosions built a complex tuff-cone, later reworked by atmospheric agents and altered by hydrothermal activity. The differences in the velocity structure between the central and eastern parts of the crater have been interpreted as resulting from a possible eastward migration of the eruptive vent along the deformational features affecting the area, and to the presence of viscous lava and lithified tuff bodies within the feeding conduits, which are buried under a covering of reworked materials of variable thickness. The observed fault and fracture systems, partially inherited from regional structural setting and exhumed during volcanism and ground deformation episodes also seems to strongly control wave propagation, affecting the noise polarization properties.
    Beschreibung: Published
    Beschreibung: Q07006
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: partially_open
    Schlagwort(e): Solfatara ; crustal structure ; seismic noise ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 53
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    A comparison of tomographic P- and S-wave speed models of the broad European and Mediterranean area (2012)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We collect and compare available three-dimensional seismological models of the earth’s upper mantle beneath the broad European and Mediterranean region, to quan- tify how well they agree. The zone we considered covers the territory from the Mid- Atlantic Ridge to the Urals, and from North Africa to the North Pole, covering an area corresponding to about one-sixth of the earth’s surface. Most of the models ac- tually cover the whole globe, but we restrict the analysis to our study sector. Avail- able tomographic P- and S-wave speed models have been computed fitting different data-sets and following a variety of inversion techniques and strategies, and may bear consequences or bias connected to the specific data-set used, or the choice made by the author. An extensive comparative investigation may thus contribute to clarify our knowledge of the deep earth structure beneath continents. The visual, qualitative level of agreement is usually rather good, particularly for the larger-scale features, such as the signatures of the East European and West African Cratons, the Mid-Atlantic Ridge, the Red Sea Rift system, the Alpine-Hymalayan belt. These traits can be identified in all models. However, quantitative comparisons do not always show high consistency among models. Model amplitudes vary considerably, and correlation analysis is not always satisfactory. We also test the ability of different models to fit group and/or phase velocity measurements, that were not used for their derivation. The test of com- patibility among different models and data-sets is a necessary preliminary step for the creation of a seismological reference earth model.
    Beschreibung: Published
    Beschreibung: Vienna-Austria
    Beschreibung: open
    Schlagwort(e): Tomography, Mediterranean area ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 54
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    Lateral Changes of seismic anisotropy in the upper mantle around the Northern Apennines (2012)
    Details
    Publikationsdatum: 2017-10-19
    Beschreibung: We performed three-dimensional analysis of anisotropic parameters of body waves to develop a 3D self-consistent dynamic model of the syn-convergent extension in the Northern Apennines within the multidisciplinary project RETREAT. Simultaneous extension within the convergent margin can be the consequence of the retreat of the subducting Adriatic plate from the orogenic front, caused by sub-lithosphere mantle processes that seismic anisotropy can help to decipher. We use data recorded by the RETREAT temporary array consisting of 35 stations complemented by data of permanent INGV observatories. Currently, 18-months of data are available from some stations, representing half of the passive experiment duration. We detect many examples of core-refracted shear-wave splitting within the upper mantle, and observe both distinct lateral variations of anisotropic parameters and their dependence on the direction of propagation. In particular, the fast shear-wave polarization changes from slab-perpendicular to slab-parallel along the Apennines chain. There is also a distinct change in the anisotropic signals across the presumed boundary of the Tyrrhenian and Adriatic micro-plates. Variations of the splitting time delays and orientation of the fast shear waves, together with considerations on the geodynamics of the area, seem to exclude simple sub-lithosphere mantle corner flow as the only source of the observed anisotropy. Alternate models include (1) a frozen-in fabric of different lithosphere domains, and (2) complex mantle flow associated with the Plio-Pleisocene uplift and extension of Tuscany.
    Beschreibung: Published
    Beschreibung: Vienna
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): anisotropy ; SKS shear wave splitting ; Northern Apennines ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
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  • 55
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    Seismic velocity structures of southern Italy from tomographic imaging of the Ionian slab and petrological inferences (2012)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2017-10-06
    Beschreibung: In this study we have determined detailed Vp and Vs seismic velocity models of the Ionian lithosphere subducting beneath the Tyrrhenian basin and of the surrounding mantle, by applying a post-processing technique to a large sample of local earthquake tomography studies. Our seismic velocity models permit us to infer the presence of low velocity anomalies within the slab, which we interpret as regions that are partially hydrated by fluids released during the subduction process. A petrological interpretation of the velocity anomalies gives new details on the magmatism of the volcanic Aeolian arc. Furthermore our velocity models provide a more detailed description of the boundary of the slab and its connection with the large seismically active Tindari-Letojanni strike slip system. Finally these results allow describing in detail some features of the slab as the presence of lateral and vertical tears. In conclusion, the obtained models provide some constraints for inferences on mantle circulation, and on the geodynamical evolution of the central-western Mediterranean.
    Beschreibung: Published
    Beschreibung: 751-764
    Beschreibung: 2.5. Laboratorio per lo sviluppo di sistemi di rilevamento sottomarini
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Tomography, petrology, Ionian slab ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 56
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    Recent tectonic reorganization of the Nubia-Eurasia convergent 2boundary heading for the closure of the western Mediterranean (2011)
    Société Géologique de France
    Details
    Publikationsdatum: 2020-11-26
    Beschreibung: : In the western Mediterranean area, after a long period (late Paleogene-Neogene) of Nubian northward subduction beneath Eurasia, subduction is almost ceased as well as convergence accommodation in the subduction zone. With the progression of Nubia-Eurasia convergence, a tectonic reorganization is therefore necessary to accommodate future contraction. Previously-published tectonic, seismological, geodetic, tomographic, and seismic reflection data (integrated by some new GPS velocity data) are reviewed to understand the reorganization of the convergent boundary in the western Mediterranean. Between northern Morocco, to the west, and northern Sicily, to the east, contractional deformation has shifted from the former subduction zone to the margins of the two backarc oceanic basins (Algerian-Liguro-Provençal and Tyrrhenian basins) and it is now active in the south-Tyrrhenian (northern Sicily), northern Liguro-Provençal, Algerian, and Alboran (partly) margins. Compression and basin inversion has propagated in a scissor-like manner from the Alboran (c. 8 Ma) to the Tyrrhenian (younger than c. 2 Ma) basins following a similar propagation of the subduction cessation and slab breakoff, i.e., older to the west and younger to the east. It follows that basin inversion is rather advanced in the Algerian margin, where a new southward subduction seems to be in its very infant stage, while it has still to properly start in the Tyrrhenian margin, where contraction has resumed at the rear of the fold-thrust belt and may soon invert the Marsili oceanic basin. GPS-derived strain rates higher in the Tyrrhenian margin than in the Algerian boundary suggest that this latter manner of contraction accommodation (contraction resumption at the rear of the orogenic wedge) is more efficient than subduction inception and basin inversion along newly-generated reverse faults (Algeria), but the differential strain rates may also be explained with the heterogeneous distribution of GPS stations. Part of the contractional deformation may have shifted toward the north in the Liguro-Provençal basin possibly because of its weak rheological properties compared with the area between Tunisia and Sardinia, where no oceanic crust occurs and seismic deformation is absent or limited compared with the adjacent strands of the Nubia-Eurasia boundary. The tectonic reorganization of the Nubia-Eurasia boundary in the study area is still strongly controlled by the inherited tectonic fabric and rheological attributes, which are both discontinuous and non-cylindrical along the boundary. These features prevent, at present, the development of long and continuous thrust faults. In an extreme and approximate synthesis, the evolution of the western Mediterranean is inferred as being similar to a Wilson Cycle in the following main steps: (1) northward Nubian subduction with Mediterranean backarc extension (since ~35 Ma); (2) progressive cessation, from west to east, of Nubian main subduction (since ~15 Ma); (3) progressive compression, from west to east, in the former backarc domain and consequent basin inversion (since ~8-10 Ma); (4) possible future subduction of former backarc basins.
    Beschreibung: Published
    Beschreibung: 279-303
    Beschreibung: 1.9. Rete GPS nazionale
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): western Mediterranean ; convergent boundary ; tectonic reorganization ; subduction, ; backarc basin ; basin inversion ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 57
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    High resolution velocity structure beneath Mount Vesuvius from seismic array data (2011)
    American Geophysical Union
    Details
    Publikationsdatum: 2012-02-03
    Beschreibung: A high resolution P-wave image of Mt. Vesuvius edifice has been derived from simultaneous inversion of travel times and hypocentral parameters of local earthquakes, land based shots and small aperture array data. The results give detailsdownto300 – 500m.Therelocatedlocalseismicity appears to extend down to 5 km below the central crater, distributed in a major cluster, centered at 3 km below the central crater and in a minor group, with diffuse hypocenters inside the volcanic edifice. The two clusters are separated by an anomalously high Vp region at around 1 km depth. A zone with high Vp/Vs in the upper layers is interpreted as produced by the presence of intense fluid circulation. The highest energy quakes (up to M = 3.6) are located in the deeper cluster, in a high P-wave velocity zone. Our results favor an interpretation in terms of absence of shallow magma reservoirs.
    Beschreibung: Published
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Velocity Tomography ; Mt. Vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 58
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    Societal need for improved understanding of climate change, anthropogenic impacts, and geo-hazard warning drive development of ocean observatories in European Seas (2011)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Society’s needs for a network of in situ ocean observing systems cross many areas of earth and marine science. Here we review the science themes that benefit from data supplied from ocean observatories. Understanding from existing studies is fragmented to the extent that it lacks the coherent long-term monitoring needed to address questions at the scales essential to understand climate change and improve geo-hazard early warning. Data sets from the deep sea are particularly rare with long-term data available from only a few locations worldwide. These science areas have impacts on societal health and well-being and our awareness of ocean function in a shifting climate. Substantial efforts are underway to realise a network of open-ocean observatories around European Seas that will operate over multiple decades. Some systems are already collecting high-resolution data from surface, water column, seafloor, and sub-seafloor sensors linked to shore by satellite or cable connection in real or near-real time, along with samples and other data collected in a delayed mode. We expect that such observatories will contribute to answering major ocean science questions including: How can monitoring of factors such as seismic activity, pore fluid chemistry and pressure, and gas hydrate stability improve seismic, slope failure, and tsunami warning? What aspects of physical oceanography, biogeochemical cycling, and ecosystems will be most sensitive to climatic and anthropogenic change? What are natural versus anthropogenic changes? Most fundamentally, how are marine processes that occur at differing scales related? The development of ocean observatories provides a substantial opportunity for ocean science to evolve in Europe. Here we also describe some basic attributes of network design. Observatory networks provide the means to coordinate and integrate the collection of standardised data capable of bridging measurement scales across a dispersed area in European Seas adding needed certainty to estimates of future oceanic conditions. Observatory data can be analysed along with other data such as those from satellites, drifting floats, autonomous underwater vehicles, model analysis, and the known distribution and abundances of marine fauna in order to address some of the questions posed above. Standardised methods for information management are also becoming established to ensure better accessibility and traceability of these data sets and ultimately to increase their use for societal benefit. The connection of ocean observatory effort into larger frameworks including the Global Earth Observation System of Systems (GEOSS) and the Global Monitoring of Environment and Security (GMES) is integral to its success. It is in a greater integrated framework that the full potential of the component systems will be realised.
    Beschreibung: Published
    Beschreibung: 1-33
    Beschreibung: 3.7. Dinamica del clima e dell'oceano
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seafloor and water columnobservatories ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 03. Hydrosphere::03.01. General::03.01.07. Physical and biogeochemical interactions ; 03. Hydrosphere::03.01. General::03.01.08. Instruments and techniques ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 03. Hydrosphere::03.03. Physical::03.03.02. General circulation ; 03. Hydrosphere::03.03. Physical::03.03.03. Interannual-to-decadal ocean variability ; 03. Hydrosphere::03.03. Physical::03.03.05. Instruments and techniques ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.05. Geomagnetism::04.05.05. Main geomagnetic field ; 04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.03. Heat generation and transport ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data ; 05. General::05.08. Risk::05.08.01. Environmental risk ; 05. General::05.08. Risk::05.08.02. Hydrogeological risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 59
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    La Tomografia sismica in velocità, attenuazione e scattering e l'immagine della struttura dei vulcani. (2011)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: a) A brief review of the results from travel time tomography at Mt. Vesuvius ed at Campi Flegrei. b) New approaches: (passive) attenuation and scattering tomography. c) Results obtained (passive attenuation and scattering) at Mt. Vesuvio and Campi Flegrei
    Beschreibung: Unpublished
    Beschreibung: Trieste
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: open
    Schlagwort(e): Attenuation ; Tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Oral presentation
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  • 60
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    The GROSMarin experiment: three dimensional crustal structure of the North Ligurian margin from refraction tomography and preliminary analysis of microseismic measurements (2011)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The deep structure of the North Ligurian margin and its contiguous Ligurian basin as well as the seismicity recorded in these zones are neither well understood nor precisely constrained. In order to better address these questions, there is a need for offshore instrumenting, which was realised for a duration of nearly 6 months during the GROSMarin (Grand Réseau d’Observation Sous-Marin) experiment. An array of 21 ocean bottom seismometers was deployed over the most active area of the margin and was complemented on land by mobile seismological stations that densified existing permanent networks. We also realised the acquisition of deep refraction seismic shots at sea in order to get a 3D distribution of velocities along the margin through travel time tomography. We present here a preliminary analysis of the seismicity recorded during this experiment and a tomographic model of the margin structures obtained using data from the offshore network only. Our results support the existence of a high velocity zone at the base of a domain interpreted as transitional between continental and oceanic ones, on the northern part of the deep basin. A very similar pattern is observed across the neighbouring margin of the Gulf of Lions and is most likely related to serpentinisation of the underlying mantle during late rifting and continental break-up. North of this transition zone, we observe the basinward crustal thinning of the continental crust beneath the margin that seemingly narrows eastward. To the south, our results hint at transition to the oceanic domain. In contrast, our velocity distribution does not reveal a transition along strike between transitional and oceanic domains, as previous works suggest. Some microseismic activity was recorded throughout the duration of the experiment, on land and at sea. The number of detected events and precision of location were both improved by our considering French and Italian permanent networks. The detection capabilities of our dense network still need to be fully exploited
    Beschreibung: Published
    Beschreibung: 305-321
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): North Ligurian margin ; Ocean bottom seismometers ; Refraction tomography ; Velocity structure ; Crustal units ; Microseismicity ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 61
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    3D Crustal Structure of the North-Ligurian Margin: First Results of the GROSMarin Experiment (2011)
    Copernicus GmbH (Copernicus Publications)
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: The North-Ligurian rifted margin is singular in that it lies immediately next to the Alpine orogenic arc. It is furthermore seismically active and can experience destructive earthquakes such as in 1887 in the region of Imperia—an event that resulted in a tsunami and more than 600 casualties in spite of a coastal area that was much less densely populated than today. Out of such rare large events, the area undergoes a limited and diffuse seismic activity that can remain undetected and is generally poorly located. This results in a poor knowledge of active structures, especially at sea. Such knowledge is however required towards a quantification of the seismic hazard along the French Riviera and the Ligurian region. To this end, the GROSMarin project was undertaken with a dual objective: (1) to characterize the North-Ligurian margin from a structural standpoint—mode and degree of crustal stretching prior to oceanic accretion, segmentation along strike, subsequent evolution in an orogenic context— and (2) to identify zones of active crustal deformation at sea that are likely to generate earthquakes. The programme is a collaborative work between GeoAzur and Dip.Te.Ris (University of Genova), with some support from INGV, IFM-GEOMAR and IFREMER. It took place from April to October 2008 and consisted in the deployment of 21 ocean-bottom seismometers (OBS) on a grid spanning 50 km along strike and 25 km across, located between Nice, France, and Imperia, Italy, and ranging from mid-slope to the deep basin. This array was extended on land by the permanent stations of the French and Italian regional networks, temporarily densified by 13 portable stations. These instruments recorded the shots of a marine seismic source towed from R/V l’Atalante and were left for more than 5 months for passive surveying. The active part of the programme aims at characterizing the main structures of the margin through crustal 3D tomography; the objective of the passive part is to decrease the detection threshold of marine microseismicity and to reach a precise location of events in order to map active faults. Some of the sea and land instruments were fitted with broadband sensors to allow for teleseismic imaging of deep lithospheric discontinuities. We present the preliminary results of this experiment—in particular a first 3D tomographic model obtained from 31.500 travel times derived from our recording of active seismic shots by the OBS’s. Passive data analysis is being under progress and first relocations have been obtained. These results give an insight into the variability of the crustal structure, both along and across strike.
    Beschreibung: Published
    Beschreibung: Vienna, Austria
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): Tomography ; Active seismology ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Abstract
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  • 62
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    A scattering image of Campi Flegrei from the autocorrelation functions of velocity tomograms (2011)
    Wiley
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: We propose a new quantitative approach for the joint interpretation of velocity and attenuation tomography images, performed through the lateral separation of scattering and intrinsic attenuation. The horizontal P-wave scattering attenuation structure below Campi Flegrei Caldera (CFC) is imaged using the autocorrelation functions (ACF) of P-wave vertical velocity fluctuations. Cluster analysis (CA) is then applied to interpret the images derived from ACF and the available P-wave total attenuation images at 2000m quantitatively. The analysis allows the separation of intrinsic and scattering attenuation on a 2-D plane, adding new geophysical constraints to the present knowledge about this volcanic area. The final result is a new, quantitative image of the past and present tectonic and volcanological state of CFC. P-wave intrinsic dissipation dominates in an area approximately located under the volcanic centre of Solfatara, as expected in a region with a large presence of fluids and gas. A north–south scattering attenuation region is mainly located below the zone of maximum uplift in the 1982–1984 bradiseismic crisis, in the sea side of the Pozzuoli bay, but also extending below Mt Nuovo. This evidence favours the interpretation in terms of a hard but fractured body, contoured by strong S-wave scatterers, corresponding to the Caldera rim: the region is possibly a section of the residual magma body, associated with the 1538 eruption of Mt Nuovo.
    Beschreibung: Published
    Beschreibung: 1304-1310
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Probability distributions ; Seismic attenuation ; Seismic tomography ; Statistical seismology ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 63
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    Deep structural heterogeneities and the tectonic evolution of the Abruzzi region (Central Apennines, Italy) revealed by microseismicity, seismic tomography, and teleseismic receiver functions (2011)
    Details
    Publikationsdatum: 2020-02-24
    Beschreibung: The crustal structure of central Apennines (Italy) is still poorly defined, leaving uncertainties on the tectonic style (thin or thick-skinned) responsible for the development of the thrust-and-fold belt. The today active extension, which replaced compression since early Quaternary, is presumably in"uenced by the pre-existing structure that yields location and segmentation of the fault system. To focus on such issues, we computed P and S-wave velocity models of the crust by using the independent methodologies of local earthquakes tomography and teleseismic receiver function. We document strong lateral and vertical heterogeneities that define shallow, imbricate sheets of the Mesozoic cover that overlay exceptionally high Vp and high Vs bodies. These bodies can be interpreted as either dolomitic or, partially hydrated, ma!c rocks. The two alternative interpretations respectively imply an ultra-thick deposition of dolomitic rocks in the hanging wall of Triassic normal fault or a deep exhumation of the Pre-Mesozoic basement during the early Mesozoic sin-rift tectonic. In both cases, these bodies in"uenced the evolution of the thrust-and-fold belt. Very remarkably, active normal faults, like those ruptured during the still ongoing 2009 L'Aquila sequence, concentrate at the border of these bodies, suggesting that they have an active role in the segmentation of the normal fault system. The rheological behavior of such high Vp high Vs bodies, weak or strong, is still uncertain, but of utmost importance to understand the risk of future normal faulting earthquakes.
    Beschreibung: Published
    Beschreibung: 462-476
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Abruzzo ; tomography ; receiver functions ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 64
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    3D tomographic imaging of the southern Apennines (Italy): A statistical approach to estimate the model uncertainty and resolution (2011)
    SPRINGER
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: A new dataset of first P-wave arrival times is used to derive the 3D tomographic model of the Campania-Lucania region in the southern Apennines (Italy). We address the issue related to the non-uniqueness of the tomographic inversion solution through massive numerical experimentation based on the global exploration of the model parameter space starting from a large variety of physically plausible initial models. The average of all the realizations is adopted as the best-fit solution and the uncertainty of the model parameters is studied using a statistical approach based on a Monte Carlo-type analysis. How the uncertainty in the initial model, earthquake locations, and data influences the inversion result is studied by considering separately the individual effects. Checkerboard tests are performed to estimate the resolving power of the dataset. Re-located seismicity in a reliable new 3D tomographic model allows us to correlate the earthquake distribution with the main seismogenic structures present in the area.
    Beschreibung: Published
    Beschreibung: 367-387
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): error analysis ; seismic tomography ; southern Apennines ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 65
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    Shallow structure of Mt. Vesuvius volcano, Italy, from seismic array analysis (2011)
    American Geophysical Union
    Details
    Publikationsdatum: 2017-05-23
    Beschreibung: SPAC method applied to data from a small aperture seismic array on Mt. Vesuvius gives the shallow velocity model.
    Beschreibung: Published
    Beschreibung: 481-484
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Array analysis ; shallow structure ; SPAC method ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 66
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    Shear-velocity andi anisotropy structure of a retreating extensional forearc (Tuscany, Italy) from receiver functions inversion (2011)
    Wiley
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We investigate in detail the crustal layering of the ‘Val di Chiana Basin’ (Northern Apennines, Tuscany, Italy) through receiver functions and seismic anisotropy with hexagonal symmetry. The teleseismic data set is recorded in correspondence of a typical foreland basin resulting by the progressive eastward retreat of a regional-scale subduction zone trapped between two continents. We study the azimuthal variations of the computed and binned receiver functions associated to a harmonic angular analysis to emphasize the presence of the dipping and the anisotropic structures. The resulting S-wave velocity model shows interesting and new results for this area that we discuss in a regional geodynamic contest contributing to the knowledge of the structure of the forearc of the subduction zone. A dipping interface (N192°E strike, 18° dip) has been revealed at about 1.5 km depth, that separates the basin sediments and flysch from the carbonates and evaporites. Moreover, we interpret the two upper-crust anisotropic layers (at about 6 and 17 km depth) as the Hercynian Phyllites and Micaschists, of the Metamorphic Tuscan Basement. At relatively shallow depths, the presence of these metamorphic rocks causes the seismic anisotropy in the upper crust. The presence of shallow anisotropic layers is a new and interesting feature, first revealed in the study area. Beneath the crust–mantle transition (Moho), located about 28 km depth, our analysis reveals a 7-km-thick anisotropic layer.
    Beschreibung: Published
    Beschreibung: 545-556
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic anisotopy ; Computational Seismology ; Wave propagation ; Subduction zone process ; Crustal structure ; Europe ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 67
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    Can local tomography settle the matter about subduction in the central and northern Apennines? (2011)
    European Seismological Commission
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The many studies conducted on the Italian area led to several models to explain the present-day structural setting. Some of the most debated questions are the presence or not of continuous subduction and the presence or not of a slab detachment in the northern or in the central part of the Apenninic chain. The absence of a continuous, high velocity body beneath the Apennines has been interpreted by some researchers as an evidence of the detachment of the Apenninic slab. According to this view the Apenninic slab is expected to be inactive whether the Ionian lithosphere subducting underneath Calabria is considered to be on the verge of detaching or just detached. Other researchers however, suggest that a fairly continuous and fast slab exists beneath the Apennines and the Calabrian arc. Different geodynamical models have also been proposed for the Tyrrhenian area considering it as an active or as a passive margin. Our working group has conducted several seismic tomographies in the search of the geometry, size and extension with depth of the subduction under the Italian peninsula. While the images resulting from teleseismic data were clearly showing a subducting slab under the Calabrian arc, they were not conclusive for the rest of the Apennines since they were showing, only in the Northern sector, a likely subduction in the shallower part apparently detached from other high velocities body in the deeper zone. At that stage it was not possible to distinguish between thrust and subduction due to the poor horizontal resolution of the applied methodology. In order to analyze in more details this apparent discrepancy, a new seismic local tomography has been conducted with a very dense grid, the selection of a smaller area to be investigated (limited to the Apennines only) and the addition of new data: all these features contributed to partly improve the results, which cannot anyway extend beyond the maximum depth of seismic events. The main limitation in this kind of experiment is the lack of seismic events deeper than 60-70 km under the northern and central Apennines although, as many authors assume, is not itself an evidence against subduction. Analyzing different cross sections of the enhanced resolution tomography results, we do not see any slab in the northern-central Apennines in the first 80-100 km depth. The downgoing material (Adriatic plate) of this area has a rather low dip angle, as also partly shown by the distribution of the (few) deep seismic events. Along the central and also the northern part of the Apennines there are more overlapping than subducting geometries.
    Beschreibung: Published
    Beschreibung: Montpellier, France
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): Tomography ; Apennines ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Abstract
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  • 68
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    Surface wave dispersion measurements from ambient seismic noise analysis in Italy (2011)
    Wiley
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present the surface wave dispersion results of the application of the ambient noise method to broad-band data recorded at 114 stations from the Istituto Nazionale di Geofisica e Vul- canologia (INGV) national broad-band network, some stations of the Mediterranean Very Broadband Seismographic Network (MedNet) and of the Austrian Central Institute for Me- teorology and Geodynamics (ZAMG). Vertical-component ambient noise data from 2005 October to 2007 March have been cross-correlated for station-pairs to estimate fundamental mode Rayleigh wave Green’s functions. Cross-correlations are calculated in 1-hr segments, stacked over periods varying between 3 months and 1.5 yr. Rayleigh wave group dispersion curves at periods from 8 to 44 s were determined using the multiple-filter analysis technique. The study region was divided into a 0.2◦ × 0.2◦ grid to invert for group velocity distribu- tions. Checkerboard tests were first carried out, and the lateral resolution was estimated to be about 0.6◦. The resulting group velocity maps from 8 to 36 s show the significant difference of the crustal structure and good correlations with known geological and tectonic features in the study region. The Po Plain and the Southern Alps evidence lower group veloci- ties due to soft alluvial deposits, and thick terrigenous sediments. Our results also clearly showed that the Tyrrhenian Sea is characterized with much higher velocities below 8 km than the Italian peninsula and the Adriatic Sea which indicates a thin oceanic crust beneath the Tyrrhenian Sea.
    Beschreibung: Published
    Beschreibung: 1242-1252
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Tomography ; Surface waves and free oscillations ; Crustal structure ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 69
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    Seismic tomography of Stromboli volcano: results from the 2006 active source experiment (2011)
    INGV - Catania
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In the text
    Beschreibung: Istituto Nazionale di Geofisica e Vulcanologia Associazione Italiana di Vulcanologia Comune di Nicolosi
    Beschreibung: Published
    Beschreibung: Nicolosi (Catania)
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: open
    Schlagwort(e): Stromboli ; seismic tomography ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Extended abstract
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  • 70
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    Shallow subduction beneath Italy: Three-dimensional images of the Adriatic-European-Tyrrhenian lithosphere system based on high-quality P wave arrival times (2010)
    American Geophysical Union
    Details
    Publikationsdatum: 2020-10-26
    Beschreibung: This paper presents a velocity model of the Italian (central Mediterranean) lithosphere in unprecedented detail. The model is derived by inverting a set of 166,000 Pg and Pn seismic wave arrival times, restricted to the highest-quality data available. The tomographic images reveal the geometry of the subduction-collision system between the European, Adriatic, and Tyrrhenian plates, over a larger volume and with finer resolution than previous studies. We find two arcs of low-Vp anomalies running along the Alps and the Apennines, describing the collision zones of underthrusting continental lithospheres. Our results suggest that in the Apennines, a significant portion of the crust has been subducted below the mountain belt. From the velocity model we can also infer thermal softening of the crustal wedge above the subducting Adriatic plate. In the Tyrrhenian back-arc region, strong and extensive low-Vp anomalies depict upwelling asthenospheric material. The tomographic images also allow us to trace the boundary between the Adriatic and the Tyrrhenian plates at Moho depth, revealing some tears in the Adriatic-Ionian subducting lithosphere. The complex lithospheric structure described by this study is the result of a long evolution; the heterogeneities of continental margins, lithospheric underthrusting, and plate indentation have led to subduction variations, slab tears, and asthenospheric upwelling at the present day. The high-resolution model provided here greatly improves our understanding of the central Mediterranean’s structural puzzle. The results of this study can also shed light on the evolution of other regions experiencing both oceanic and continental subduction.
    Beschreibung: Published
    Beschreibung: B05305
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): lithosphere ; crust ; italy ; plates ; subduction ; europe ; seismicity ; adria ; tyrrhenian ; boundary ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 71
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    The stress-field variation on the italian active volcanic areas: the shear wave splitting monitoring (2010)
    INGV - Catania
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In the text
    Beschreibung: Istituto Nazionale di Geofisica e Vulcanologia Associazione Italiana di Vulcanologia Comune di Nicolosi
    Beschreibung: Published
    Beschreibung: Nicolosi (Catania)
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: open
    Schlagwort(e): Splitting ; Volcano monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Extended abstract
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  • 72
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    Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) (2010)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. A well-scattered distribution of single shear-wave measurements has been obtained. Average values show clearly that dominant fast axis direction is NE-SW oriented, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we inferred the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we have modelling waveforms using a cross-convolution technique in one and two anisotropic layer's cases. We obtained a significant improvement on the misfit in the double layer case for the cited couple of stations. For stations where a multi-layer structure does not fit, we looked for evidences of lateral anisotropy changes at depth through Fresnel zone computation. As expected, we find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics.
    Beschreibung: Submitted
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Antarctica ; Shear-wave splitting ; Seismic Anisotropy ; Mantle processes ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: manuscript
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  • 73
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    Structure of the Antarctic plate by analysis of surface-wave group speed and a global Haar-wavelet model representation (2010)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The unique tectonic setting of the Antarctic plate — all surrounded by active ocean ridges, geodynamically stationary, and crossed by the largest asymmetric continental rift — make it a very interesting subject, that recently has received increased attention because of the International Polar Year (IPY). We present a seismic tomographic study targeted at improving the resolution of previous models, by virtue of an extended dataset and a multiresolution spherical-wavelet based model representation. We limit the present study to modeling laterally-varying fundamental-mode Rayleigh wave group speed, that is mainly related to the structure of crust and uppermost mantle. We use single-station dispersion analysis on the surface wave train to measure group arrival times of the Rayleigh-wave fundamental mode in the period range between 30 and 150 s. On each seismogram we iteratively apply a multiple filter – to identify group arrival times with frequency – and a phase-matched filter, to isolate the fundamental mode within the wave train. We then use dispersion measurements to compute two-dimensional maps of wave group speed in the region. We parameterize the Earth using nearly-orthogonal spherical Haar wavelets based on iterative subdivisions of the icosahedron. This representation is particularly suited to implement multi-resolution, as needed for a regional model embedded into a global one. The model shows with increased detail important features such as the narrow transition between cratonic structure in East Antarctica and accreted West Antarctica, separated by the Transantarctic Mountains bordering the rift. Inclusion of data from temporary experiments carried on within the IPY, as they become available, will locally further improve resolution.
    Beschreibung: Unpublished
    Beschreibung: Vienna
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): seismic tomography ; wavelet analysis ; Antarctica ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 74
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    Imaging lateral heterogeneity in the northern Apennines from time reversal of reflected surface waves (2010)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Prominent arrivals in the coda of seismograms from the wider Alpine area can be associated with lateral reflections of Love waves at the northern Apennines mountain chain (Italy), where structural heterogeneity causes an abrupt contrast in phase velocity. We discuss an approach to image lateral heterogeneity from reflected surface waves using intermediate-period, three- component coda waveforms as sources for an adjoint wavefield that propagates the reflections backward in time. We numerically compute three-dimensional sensitivity kernels for the dependence of coda waveforms on P velocity, S velocity and density, based upon correlations between the adjoint and the regular forward wavefields. We consider synthetic coda waveforms for a simplified model of the northern Apennines, as well as real coda observations from five moderate magnitude earthquakes (M W 4.6–5.6) in the southern Alps. Wave propagation is simulated using the spectral-element method, for which a 3-D regional earth model is used in the case of real data. Single and combined event sensitivity kernels provide clear images of the reflectivity associated with the northern Apennines in kernels for density and S-wave speed. The kernels show that surface wave reflections occur near the axial zone of the mountain chain. Apart from the Apennines, the approach is able to image other smaller reflectivity patches from the coda waveforms, like the Ivrea zone in the southern Alps. Our coda misfit kernels can be integrated in a gradient-based waveform tomography, where they could enhance the shar pness of the model at lateral discontinuities.
    Beschreibung: Published
    Beschreibung: 543–554
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Tomography; ; Computational seismology ; Wave scattering and diffraction ; Crustal structure ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 75
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    3D Scattering Image of Mt. Vesuvius (2010)
    SEISMOLOGICAL SOC AMER
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: In this article we apply a passive scattering-imaging method, derived from the method developed by Nishigami (1991) to data from the coda of the local volcano-tectonic (VT) earthquakes of Mt. Vesuvius. This method provides the space distribution of the strong scatterers together with a rough estimate of their strength. In the development of our method we use a realistic raytracing calculated with a raybending approach in the 3D velocity model of Mt. Vesuvius structure obtained with travel-time inversion. The inversion procedure adopted for the scattering imaging in the present study is based on the conjugate gradient method (CGM). The volume under study is divided into cubic cells with different dimensions in a multiscale approach. We obtain the best resolution (900 m cubic cell size) in the central part of the volume under study (roughly in a radius of 4 km centered in the crater) within a depth of 5 km. We analyzed the coda signals after filtering in two frequency bands, the first centered at 12 Hz and the second at 18 Hz, where most of the seismic energy is concentrated. Results show that most of the strong scatterers are located in the depth range between the surface and 3000 m below the sea level, in correspondence with the crater axis where most of the seismicity occurs. Part of the scatterers are located in the zones characterized by the maximum velocity contrasts.
    Beschreibung: Published
    Beschreibung: 1962–1972
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mt. Vesuvius ; scattering-imaging ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 76
    facet.materialart.
    Unbekannt
    Seismic Anisotropy in the Victoria Land Region (Antarctica) (2010)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. A well-scattered distribution of single shear-wave measurements has been obtained. Average values show clearly that dominant fast axis direction is NE-SW oriented, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we inferred the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we have modelling waveforms using a cross-convolution technique in one and two anisotropic layer's cases. We obtained a significant improvement on the misfit in the double layer case for the cited couple of stations. For stations where a multi-layer structure does not fit, we looked for evidences of lateral anisotropy changes at depth through Fresnel zone computation. As expected, we find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics.
    Beschreibung: Submitted
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Antarctica ; Seismic Anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: manuscript
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  • 77
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    Standardization of Seismic Tomographic Models and Earthquake Focal Mechanisms Datasets Based on Web Technologies, Visualization with Keyhole Markup Language (2010)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present two projects in seismology that have been ported to web technologies, which provide results in Keyhole Markup Language (KML) visualization layers. These use the Google Earth geo-browser as the flexible platform that can substitute specialized graphical tools to perform qualitative visual data analyses and comparisons. The Network of Research Infrastructures for European Seismology (NERIES) Tomographic Earth Model Repository contains datasets from over 20 models from the literature. A hierarchical structure of folders that represent the sets of depths for each model is implemented in KML, and this immediately results into an intuitive interface for users to navigate freely and to compare tomographic plots. The KML layer for the European-Mediterranean Regional Centroid-Moment Tensor Catalog displays the focal mechanism solutions or moderate magnitude Earthquakes from 1997 to the present. Our aim in both projects was to also propose standard representations of scientific datasets. Here, the general semantic approach of XML has an important impact that must be further explored, although we find the KML syntax to be more shifted towards detailed visualization aspects. We have thus used, and propose the use of, Javascript Object Notation (JSON), another semantic notation that stems from the web-development community that provides a compact, general-purpose, data-exchange format.
    Beschreibung: In press
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: 5.2. TTC - Banche dati di sismologia strumentale
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): seismology ; geophysics ; json ; googleEarth ; kml ; xml ; web standards ; semantic data ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 78
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    Seismic attenuation imaging of Campi Flegrei: Evidence of gas reservoirs, hydrothermal basins, and feeding systems (2010)
    Agu
    Details
    Publikationsdatum: 2019-03-05
    Beschreibung: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.
    Beschreibung: Passive high‐resolution attenuation tomography is used here to image the geological structure in the first upper 4 km of the shallow crust beneath the Campi Flegrei caldera, southern Italy. The inverse Q was estimated for each source‐receiver path using the coda‐normalization method (S‐waves) and the slope decay method (P‐waves and S‐waves). Inversion was performed using a multi‐resolution method, which ensures a minimum cell‐size resolution of 500 m. The study of the resolution matrix as well as the synthetic tests guarantee an optimal reproduction of the input anomalies in the center of the caldera, between 0 and 3.5 km in depth. High attenuation vertical structures are connected at the surface with the main volcanological features (e.g., the Solfatara and Mofete fumarole fields), and depict vertical Q contrast imaging important geological structures, such as the La Starza fault. These high attenuation volumes extend between the surface and a depth of about 3 km, where a hard rock layer is imaged by the sharp contrast of the quality factors. The retrieved image of the Campi Flegrei has been jointly interpreted taking into account evidence from seismological, geological, volcanological and geochemical investigations. This analysis has allowed an unprecedented view of the feeding systems in this area, and in particular it recognizes the vertically extending, high attenuation structures that correspond to gas or fluid reservoirs beneath Pozzuoli‐Solfatara, Solfatara, Mofete‐Mt. Nuovo and Agnano. This high‐attenuation system is possibly connected with the magma sill revealed at about 7 km in depth by passive travel‐time tomography.
    Beschreibung: Published
    Beschreibung: B09312
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Campi Flegrei ; gas ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 79
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    Multiple resolution seismic attenuation imaging at Mt. Vesuvius (2010)
    Elsevier
    Details
    Publikationsdatum: 2019-03-05
    Beschreibung: A three-dimensional S wave attenuation tomography of Mt. Vesuvius has been obtained with multiple measurements of coda-normalized S-wave spectra of local small magnitude earthquakes.We used 6609 waveforms, relative to 826 volcano-tectonic earthquakes, located close to the crater axis in a depth range between 1 and 4 km (below the sea level), recorded at seven 3-component digital seismic stations. We adopted a two-point ray-tracing; rays were traced in an high resolution 3-D velocity model. The spatial resolution achieved in the attenuation tomography is comparable with that of the velocity tomography (we resolve 300m side cubic cells). We statistically tested that the results are almost independent from the radiation pattern. We also applied an improvement of the ordinary spectral-slope method to both P- and S-waves, assuming that the differences between the theoretical and the experimental high frequency spectral-slope are only due to the attenuation effects. Consequently we could check the codanormalization method also comparing the S attenuation image with the P attenuation image. The images were obtained inverting the spectral data with a multiple resolution approach. Results have shown the general coincidence of low attenuation with high velocity zones. The joint interpretation of velocity and attenuation images allows us to interpret the low attenuation zone intruding toward the surface until a depth of 500m below the sea level as related to the residual part of solidified magma from the last eruption. In the depth range between −700 and −2300 images are consistent with the presence of multiple acquifer layers. No evidence of magma patches greater than the minimum cell dimension (300m) has been found. A shallow P wave attenuation anomaly (beneath the southern flank of the volcano) is consitent with the presence of gas saturated rocks. The zone characterized by the maximum seismic energy release cohincides with a high attenuation and low velocity volume, interpreted as a cracked medium.
    Beschreibung: Published
    Beschreibung: 17–32
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Attenuation tomography ; Mt. Vesuvius ; Coda normalization method ; Spectral slope ; Multi resolution inversion ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 80
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    Unbekannt
    Crustal heterogeneity highlighted by spatial b-value map in theWellington region of New Zealand (2010)
    Wiley-Blackwell
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We map the b-value in the subduction zone of theWellington region, NewZealand, using a high quality earthquake catalogue relocated with a 3-D seismic velocity model, consisting of 50 314 events that occurred between 1990 and 2005. In order to investigate heterogeneity in the crust of the overlying plate and in the upper plane of the Wadati–Benioff Zone (WBZ), we analyse a series of cross-sections perpendicular to the strike of the subduction zone. We calculate the b-values selecting events with magnitude of completeness ≥2.4 and depth ≤65 km and projecting the seismicity within 20 km on each side of the cross-sectional planes. We observe areas of high b-value (∼1.7) near the plate interface and regions of low b-value anomalies are detected both in the WBZ in the northwest region below 40 km depth and in the overlying plate in the northern South Island at 10 km depth. The anomalies are statistically significant based on Utsu’s p-test and the bootstrap method and are not data processing method or parameter dependent. We compare the b-value distribution with previously determined 3-D distributions of Vp, Vp/Vs andQp from seismic tomography. This comparison suggests that material inhomogeneity, caused by fluid filled cracks resulting from dehydration of the subducted slab and subducted sediments, is the predominant cause of b-value variation in the shallow part of this subduction zone. Our observations are consistent with a previously proposed conceptual model that fluid distribution in the shallow part of this subduction zone is controlled by the permeability of geological terranes in the overlying plate.
    Beschreibung: Published
    Beschreibung: 451-460
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismic attenuation ; Seismic tomography ; Statistical seismology ; Subduction zone processes ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 81
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    Unbekannt
    Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) (2010)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. A well-scattered distribution of single shear-wave measurements has been obtained. Average values show clearly that dominant fast axis direction is NE-SW oriented, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNWSSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we inferred the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we have modelling waveforms using a cross-convolution technique in one and two anisotropic layer’s cases. We obtained a significant improvement on the misfit in the double layer case for the cited couple of stations. For stations where a multi-layer structure does not fit, we looked for evidences of lateral anisotropy changes at depth through Fresnel zone computation. As expected, we find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NESW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics.
    Beschreibung: Published
    Beschreibung: Vienna
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): Seismic Anisotropy ; Mantle processes ; Antarctica ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 82
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    Shear-wave velocity structure at Mt. Etna from inversion of Rayleigh-wave dispersion patterns (2 s 〈 T 〈 20 s) (2010)
    Istituto Nazionale di Geofisica e Vulcanologia
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In the present study, we investigated the dispersion characteristics of medium-to-long period Rayleigh waves (2 s 〈 T 〈 20 s) using both singlestation techniques (multiple-filter analysis, and phase-match filter) and multichannel techniques (horizontal slowness [p] and angular frequency [~] stack, and cross-correlation) to determine the velocity structure for the Mt. Etna volcano. We applied these techniques to a dataset of teleseisms, as regional and local earthquakes recorded by two broad-band seismic arrays installed at Mt. Etna in 2002 and 2005, during two seismic surveys organized by the Istituto Nazionale di Geofisica e Vulcanologia (INGV), sezione di Napoli. The dispersion curves obtained showed phase velocities ranging from 1.5 km/s to 4.0 km/s in the frequency band 0.05 Hz to 0.45 Hz. We inverted the average phase velocity dispersion curves using a non-linear approach, to obtain a set of shear-wave velocity models with maximum resolution depths of 25 km to 30 km. Moreover, the presence of lateral velocity contrasts was checked by dividing the whole array into seven triangular sub-arrays and inverting the dispersion curves relative to each triangle.
    Beschreibung: Published
    Beschreibung: 69-78
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Mount Etna ; Rayleigh-wave dispersion ; S-wave velocity model ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 83
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    Unbekannt
    Complex wavelet transform: an application to retrieve shear wave splitting time behavior at Mt. Vesuvius (2010)
    OGS, Trieste
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Shear wave splitting is the elastic-equivalent of the well-known phenomenon of optical birefringence. A shear wave propagating through an anisotropic volume splits into two S waves (qS1 and qS2) that travel with different velocities and different polarization directions. This process generates two observables: Td that is the time delay between the two split S-waves, and the polarization direction of the faster one, qS1. In the upper crust this phenomenon has been interpreted to occur in zones of fluid-filled cracks, microcracks or preferentially oriented pore spaces. The time evolution of anisotropic distribution of microcracks due to a differential stress, according to the nonlinear anisotropic poroelasticity (APE) model, is explained by the fluid migration along pressure gradients between neighboring microcracks and pores. In this framework the shear wave splitting parameters are indicators of the state of stress in the upper crust. We obtained shear wave splitting measurements for local earthquakes occurred before the largest earthquake (M= 3.6 occurred October 9th, 1999) recorded at Mt. Vesuvius after the last eruption (March 1944). The arrival times of split shear waves and the polarization directions were detected by using the wavelet transform of a three-component signal. In order to avoid any spatial effects on the time behavior of the parameters, we performed the analysis for a selected dataset of doublets. Short term (of the order of tenth of days) variation of both Td and qS1 parameters are retrieved before the occurrence of the M=3. 6 event.
    Beschreibung: Published
    Beschreibung: 253-263
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): wave splitting ; wavelet transform ; Mt. Vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 84
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    Earthquake relocation and three-dimensional V p and V p/V s models along the low angle Alto Tiberina Fault (Central Italy): evidence for fluid overpressure (2009)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The active extension in the central portion of the northern Apennines is believed to be accommodated by an ENE-dipping low-angle normal fault cutting the upper crust, called Alto Tiberina Fault (ATF). The physical properties and mechanics of such a severely misoriented fault are still unknown and debated. In this study, we constrain the deep geometry of the ATF and investigate the material properties of the fault system by using microseismicity recorded by a dense local seismic network. The inversion of local earthquake P- and S-wave arrival times yields high resolution Vp and Vp/Vs images of the fault system. We find positive Vp anomalies that define the eastward verging thrust-and-fold belt developed in the sedimentary cover, which inner bulk consists of Triassic evaporites, remains of the older compression. Microseismicity reveals the 20°NE-dipping ATF, nearly planar from 3 to 14 km depth. No sharp velocity contrasts are observed across the fault, but only a gentle warping of the velocity anomalies and the dislocation of the Triassic evaporites top at shallow depth. On the fault hangingwall, normal Vp and strong high Vp/Vs indicate the presence of a fractured high fluid pressure volume, within which steep normal fault segments are located. This evidence suggests that fluid pressure plays a dominant role in triggering the shallow background seismicity. Along the ATF, low Vp/Vs anomalies are observed, suggesting a different level of cracking and pore saturation and that the fault acts as impermeable barrier. We speculate that the microseismic activity on the ATF is favoured by the entrapped and locally overpressured CO2 testified by the low Vp/Vs volumes.
    Beschreibung: Published
    Beschreibung: 833-846
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic tomography ; Seismicity and tectonics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 85
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    Unbekannt
    Surface wave tomography in the European and Mediterranean region (2009)
    Blackwell Publishing
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We present a new surface-wave tomographic study of the broad European and Mediterranean region. Our goal is to enhance the resolution of previously published group velocity models using new data from European permanent seismic networks and a dense broad-band array in Northern Apennines (RETREAT). We measure fundamental mode Rayleigh and Love wave group velocities from long-period seismograms recorded at regional distance (between 600 and 7000 km). Our measurement technique is based on iterative application of multiple filters and phase-matched filters; we accurately estimate dispersion curves for more than 1500 Rayleigh wave and about 850 Love wave paths in the period range 35–170 s. Consistency of measurements is evaluated by comparing ray clusters from sample earthquakes to closely spaced RETREAT stations. In the whole data set, measurement errors in group velocity decrease with increasing distance and show to be caused by inaccuracy in the estimate of group arrival time. We calculate maps of Love and Rayleigh group velocity at selected periods by linear tomographic inversion, accounting for group arrival time errors and evaluating a posteriori group slowness errors. Data coverage in this region is not uniform, and it is highly influenced by the uneven distribution of earthquakes and seismic stations. We therefore build a laterally heterogeneous reference model by inverting a global data set of group velocity derived from the phase velocity library of Ekström et al. (1997). Use of this reference as an a priori model during inversion improves preliminary data coverage at the borders of our study region and warrants consistency with global models. The implications of different regularization constraints (mathematically equivalent to norm damping or smoothing with different criteria) are analysed and compared. Group velocity maps confirm the large-scale geological lineaments known for the region: short-periods maps differentiate well among thinner oceanic and thicker continental crust; the most dominant feature in long-period maps is the difference between the fast Precambrian East European Platform and the low velocity signature of central Europe and western Mediterranean, separated by a sharp gradient in correspondence of the Tornquist–Tesseyre Zone. The seismically active Tethyan Belt is clearly marked by a continuous slow anomaly. Smaller scale, possibly thermally related, low velocity anomalies are found under Iceland and Mid-Atlantic Ridge, Rhine Graben and Tyrrhenian back-arc basin, whereas the Hellenic Arc is characterized by fast velocity.
    Beschreibung: NERIES INFRAST-2.1-026130 SPICE EC FP6 Marie Curie RTN
    Beschreibung: Published
    Beschreibung: 1050-1066
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Inverse theory ; Surface waves and free oscillations ; Seismic tomography ; Europe ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 86
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    Tomographic images and analysis of stress and strain tensors at Mt. Etna: the magmatic unrest leading to the 2008 Etna eruption (2009)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We analysed the seismic activity preceding and accompanying the onset of the 2008 Mt. Etna eruption. Since January 2008, a clear seismic evidence of a magmatic unrest of the volcano was observed. Seismicity was firstly located in the southwestern sector of the volcano, at depth ranging between 10 and 20 km, along two tectonic structures (NE-SW and NNW-SSE) usually associated with deeper magmatic recharge mechanisms (Figs. 1, 2). Afterwards, the seismicity was located along the shallower portions of the main structures of the northeastern and southern flanks of the volcano (Figs. 1, 2). On May 13, 2008 an intense seismic swarm (about 230 events in 7 hours) announced the beginning of the eruption (Fig. 1, white circles). In order to provide seismological constraints to the magmatic unrest of the volcano, 336 earthquakes recorded from January 2007 to May 2008 (magnitude greater than 1.0) were selected for stress and strain tensors computation and 3D velocity and attenuation structure determination. This in order to individuate possible stress variations caused by the activation of magmatic sources which can be well evidenced by 3D tomographic images.
    Beschreibung: Published
    Beschreibung: Rome
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: open
    Schlagwort(e): Mt. Etna ; Tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Conference paper
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  • 87
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    Double-difference tomography at Mt Etna volcano: Preliminary results (2009)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We performed a preliminary double-difference tomographic study using earthquake data recorded by the INGV-Catania seismic network during the large seismic and eruptive crisis of 2002-2003 at Mt Etna volcano. Compared to previous models, first results presented from the inversion of travel-time differences, tend to show an increase in the velocity contrast between the fast core and the slow periphery of the volcano.
    Beschreibung: Published
    Beschreibung: 74-84
    Beschreibung: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Beschreibung: open
    Schlagwort(e): Mt. Etna ; double-difference tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book chapter
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  • 88
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    Deep geometry and rheology of an orogenic wedge developing above a continental subduction zone: Seismological evidence from the northern-central Apennines (Italy) (2009)
    Geological Society of America
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Data from high-density seismic networks deployed between 2000 and 2007 in the north-central Apennines (Italy) yield unprecedented images of an active orogenic wedge. Earthquake foci from the northern Apennines define a Benioff zone deepening westward from the Adriatic foreland down to ~60 km depth below the chain. The seismicity shows that only the lowermost ~10 km of the Adriatic foreland crust is subducted, whereas the uppermost ~20 km is incorporated into the orogenic wedge. Farther west, an aseismic mantle with markedly negative P-wave-velocity (Vp) anomalies is interpreted as asthenosphere flowing toward an Adriatic slab in retrograde motion. Three crustal layers with different Vp and seismicity characteristics are imaged below the northern Apennines: an uppermost 10-km-thick fast layer affected by extensional faulting, a slow layer with diffuse seismicity down to ~15 km depth, and a lowermost fast and aseismic layer resting directly above the asthenosphere. We interpret the latter layer as having formed by anhydrous crust undergoing granulitization, whereas trapped CO2 (either from the underlying granulites or from the subducting Adriatic crust) is inferred to have been responsible for both low Vp and diffuse seismicity in the middle crust. Trapped CO2 is released along the easternmost normal fault systems breaking the Apennine upper crust, consistent with geochemical and seismotectonic evidence. Compressive earthquakes at 20–25 km depth along the external front suggest offscraping of the subducting foreland crust and show that asthenospheric flow represents the primary source of ongoing shortening along the belt front.
    Beschreibung: Published
    Beschreibung: 95-104
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: N/A or not JCR
    Beschreibung: reserved
    Schlagwort(e): Northern Apennines ; subduction ; orogenic wedge ; seismology ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 89
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    The Mt Etna 2001-2003 eruptive period: the seismological point of view (2009)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: During 2001 and 2002-2003 Mount Etna produced two significant flank eruptions. Many similarities between the two eruptions have been recognized by several authors regarding the high degree of explosivity, the location of the eruptive centres and the emission of different compositionally distinct magma types. A new tomographic study concerning the 2001-2003 interval time including the two lateral eruptions is here presented, which take into account precise earthquake locations. The used algorithm was the double-difference seismic tomography method (TomoDD), which uses both absolute and differential arrival times to simultaneously determine event locations and Vp and Vp/Vs velocity models. Firstly, we performed a tomographic inversion on the whole dataset consisting of 1,035 local earthquakes occurred from July 2001 to January 2003, combining 14,205 P-wave and 3,337 S-wave arrival time differences. After, we separately analysed the 2001, 2002-2003 and intra eruptive datasets to obtain the tomographic images in the three distinct periods. The tomographic inversion during the eruptive periods revealed the presence of anomalous volumes with very low Vp/Vs (values as small as 1.64) located in the same place of the 2001 and the 2002-2003 dike intrusions also evidenced by attenuation tomographies and modeled by geodetic data. We suggest that these anomalies trace the intrusion of volatile-rich magma leading to these peculiar explosive eruptions. In the tomograms related to the intra-eruptive period some variations in the elastic parameters have also been observed. The analysis of the geodetic and seismic deformation pattern in the intra eruptive period suggested that during 2001 –2003 period the active deformation at Mt Etna has been continuous, excluding a brief period of deflation following the 2001 eruption. In fact, after this period, the seismicity rate remained high, the geodetic data showed a renewal of the areal dilatation, suggesting a new magma upraising from depth causing an overpressure in the shallow reservoir which triggered the 2002-2003 eruption.
    Beschreibung: Published
    Beschreibung: Reykjavik
    Beschreibung: open
    Schlagwort(e): Mt. Etna ; tomography ; stress and strain seismic ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 90
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    Tomographic images of a low velocity Vp and Vs volume beneath Stromboli Volcano, Italy (2009)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The present study is mainly focused to determine the hypocentral locations and the velocity structure between the northeastern Sicily and southern Calabria, including the Aeolian Archipelago with particular regard to Stromboli volcano. The main goals are: i) to explore the differences between relative and absolute earthquake locations, ii) to identify spatial clusters in the seismicity, in order to investigate on the most active seismogenic zones and structures and iii) to recognize the presence of low velocity regions beneath the Aeolian Archipelago related to the presence of partial melting. We applied the TomoDD algorithm which use both absolute and differential arrival times to simultaneously determine event locations and Vp and Vp/Vs velocity models. 1,304 well located events have been considered during the 1994-2006 period. This code was applied to the catalog phase data, combining 11,261 P-wave and 5,751 S-wave arrival time differences. On the basis of the distribution of the events, a denser grid with respect to previous studies was used. This allowed a higher resolution of the velocity model and to find a better correspondence with the most active seismogenic zones and structures. Moreover, being the velocity structure of Stromboli poorly defined, a particular attention was devoted to this area. Tomographic images beneath this volcano revealed the presence of a low Vp and Vs (average values around 5.4 and 3.1 Km/s, respectively) elongated volume in the crust, suggesting the existence of partial melting. This volume extending until 17 km of depth, overlies a high Vp and Vs (values greater than 7.5 and 4.5 km /s, respectively) region that can be related to the Moho.
    Beschreibung: Published
    Beschreibung: Reykjavik
    Beschreibung: open
    Schlagwort(e): Tomography ; Stromboli ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 91
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    Double-difference tomography at Mt. Etna volcano (2009)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Double-difference tomography at Mt Etna volcano was realized by using the tomographic algorithm developped by Monteiller et al. (2005), in which the travel-time computation was performed using a finite-difference solution of the Eikonal equation (Podvin and Lecomte, 1991) and a posteriori ray-tracing. The inverse problem was solved using a probabilistic approach (Tarantola and Valette, 1982). The optimal a priori information (correlation length and a priori model variance) was found experimentally by performing tomographies for correlation lengths and variances varying in large intervals. This probabilistic approach allowed us to use a sech pdf for representing errors in differential times. Data were travel-times and time delays provided by a set of 329 earthquakes, well-recorded by the INGV-CT seismic network (50 stations) on the Mt Etna volcano during the seismo-volcanic crisis occurring between October 2002 and January 2003. Checkerboard tests realized with this geometry and earthquake pairs showed that the model can be correctly reconstructed in a significant area around Mt Etna volcano. Results of the P and S-wave double-difference tomography clearly evidenced two concentric features: a fast central cylindrical core, probably of intrusive origin, surrounded by a slow annealed body, which could be related to partial melting.
    Beschreibung: Published
    Beschreibung: Vienna
    Beschreibung: open
    Schlagwort(e): Mt. Etna ; double-difference tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 92
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    P wave seismic velocity and Vp/Vs ratio beneath the Italian peninsula from local earthquake tomography (2008)
    Elsevier
    Details
    Publikationsdatum: 2020-11-17
    Beschreibung: We investigate the P wave velocity structure and the Vp/Vs ratio beneath the Italian peninsula down to 100 and 60 km depth respectively by seismic travel time tomography. We invert data provided by the International Seismological Centre (ISC) (1997–2005), making use of some alternative strategies for the travel time approach in a well constrained and worldwide adopted code (SIMULPS). Resolution for the different layers is discussed and sensitivity analyses are performed through test inversions to explore the resolution characteristics of the model at different spatial scales. The resulting tomographic images provide a detailed sketch of the P wave anomalies, clearly showing, among the other features, the shape of the Ivrea body in the Western Alps, the upwelling of the oceanic crust in the Ligurian Sea and the slab under the Calabrian arc. They are less informative for the Vp/Vs ratio. Nevertheless, some features are very interesting and deserve further investigation like the anomalous decrease of the Vp/Vs ratio under the Ligurian Sea or the variations of the Vp/Vs ratio calculated in the first 10 km depth of the Apenninic region with respect to the lower values of the Alpine region at the same depth. The tomographic cross sections reveal a continuous superposition of two kinds of crusts (transitional over Adriatic) all along the peninsula but do not show any slab, intended as a clear, vertical downgoing high velocity material in either the northern or central Apennines.
    Beschreibung: Published
    Beschreibung: 1-23
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic tomography ; Lithospheric structure ; Vp/Vs ratio ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 93
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    Unbekannt
    A reappraisal of shear wave splitting parameters from Italian active volcanic areas through a semiautomatic algorithm (2008)
    Springer Netherlands
    Details
    Publikationsdatum: 2020-11-17
    Beschreibung: Shear wave splitting parameters represent a useful tool to detail the stress changes occurring in volcanic environments before impending eruptions. In the present paper, we display the parameter estimates obtained through implementation of a semiautomatic algorithm applied to all useful datasets of the following Italian active volcanic areas:Mt. Vesuvius,Campi Flegrei, and Mt. Etna. Most of these datasets have been the object of several studies (Bianco et al., Annali di Geofisica, XXXXIX 2:429–443, 1996, J Volcanol Geotherm Res 82:199–218, 1998a, Geophys Res Lett 25(10):1545–1548, 1998b, Phys Chem Earth 24:977–983, 1999, J Volcanol Geotherm Res 133:229–246, 2004, Geophys J Int 167(2):959–967, 2006; Del Pezzo et al., Bull Seismol Soc Am 94(2):439–452, 2004). Applying the semiautomatic algorithm, we confirmed the results obtained in previous studies, so we do not discuss in much detail each of our findings but give a general overview of the anisotropic features of the investigated Italian volcanoes. In order to make a comparison among the different volcanic areas, we present our results in terms of the main direction of the fast polarization (ϕ) and percentage of shear wave anisotropy (ξ )
    Beschreibung: Published
    Beschreibung: 253–266
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Shear wave splitting parameters ; Temporal variations ; Volcano seismology ; Semiautomatic techniques ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 94
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    Unbekannt
    Seismic Tomography Experiment at Italy's Stromboli Volcano (2008)
    American Geophysical Union
    Details
    Publikationsdatum: 2021-07-14
    Beschreibung: From 25 November to 2 December 2006, the first active seismic tomography experiment at Stromboli volcano was carried out with the cooperation of four Italian research institutions. Researchers on board the R/V Urania of the Italian National Council of Research (CNR), which was equipped with a battery of four 210- cubic- inch generated injection air guns (GI guns), fired more than 1500 offshore shots along profiles and rings around the volcano.
    Beschreibung: DPC/INGV agreement 2004-2006
    Beschreibung: Published
    Beschreibung: 269-270
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: N/A or not JCR
    Beschreibung: reserved
    Schlagwort(e): Stromboli ; seismic tomography ; air-gun ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 95
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    Unbekannt
    SKS splitting in Southern Italy: anisotropy variations in a fragmented subduction zone. (2008)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: In this paper we present a collection of good quality shear wave splitting measurements in Southern Italy. In addition to a large amount of previous splitting measurements, we present new data from 15 teleseisms recorded from 2003 to 2006 at the 40 stations of the CAT/SCAN temporary network. These new measurements provide additional constraints on the anisotropic behaviour of the study region and better define the fast directions in the southern part of the Apulian Platform. For our analysis we have selected wellrecorded SKS phases and we have used the method of Silver and Chan to obtain the splitting parameters: the azimuth of the fast polarized shear wave (φ) and delay time (δt). Shear wave splitting results reveal the presence of a strong seismic anisotropy in the subduction system below the region. Three different geological and geodynamic regions are characterized by different anisotropic parameters. The Calabrian Arc domain has fast directions oriented NNE–SSW and the Southern Apennines domain has fast directions oriented NNW–SSE. This rotation of fast axes, following the arcuate shape of the slab, is marked by a lack of resolved measurements which occurs at the transition zone between those two domains. The third domain is identified in the Apulian Platform: here fast directions are oriented almost N–S in the northern part and NNE–SSW to ENE–WSW in the southern one. The large number of splitting parameters evaluated for events coming from different back-azimuth allows us to hypothesize the presence of a depth-dependent anisotropic structure which should be more complicated than a simple 2 layer model below the Southern Apennines and the Calabrian Arc domains and to constrain at 50 km depth the upper limit of the anisotropic layer, at least at the edge of Southern Apennines and Apulian Platform. We interpret the variability in fast directions as related to the fragmented subduction system in the mantle of this region. The trench-parallel φ observed in Calabrian Arc and in Southern Apennines has its main source in the asthenospheric flow below the slab likely due to the pressure induced by the retrograde motion of the slab itself. The pattern of φ in the Apulian Platform does not appear to be the direct result of the rollback motion of the slab, whose influence is limited to about 100 km from the slab. The anisotropy in the Apulian Platform may be related to an asthenospheric flow deflected by the complicated structure of the Adriatic microplate or may also be explained as frozen-in lithospheric anisotropy.
    Beschreibung: Published
    Beschreibung: 49-67
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: partially_open
    Schlagwort(e): Shear wave splitting ; Subduction ; Mantle flow ; Southern Italy ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 96
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    Unbekannt
    Struttura crostale e subcrostale della penisola italiana dalla interpretazione congiunta di immagini tomografiche e profile DSS (2008)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Questo studio rappresenta la conclusione di una serie di analisi precedentemente proposte e volte alla migliore comprensione della struttura profonda della penisola italiana. Tale serie, iniziata con il confronto tra la sismicità crostale e le interpretazioni dei profili DSS (Cassinis e Solarino, 2004; Cassinis e Solarino, 2006), si era successivamente estesa alla struttura litosferica (Solarino e Cassinis, 2005; Solarino e Cassinis, 2007). In ambedue le occasioni lo studio era stato condotto avendo cura di utilizzare le più recenti elaborazioni dei profili e selezionando gli ipocentri con criteri molto restrittivi. Nello spirito dei precedenti lavori, anche in questo caso si è eseguita una analisi congiunta di dati ottenuti con diverse tecniche sovrapponendo alle interpretazioni già esistenti le informazioni ricavate da un recente studio tomografico (Scafidi et al., 2008) effettuato con la tecnica della inversione di terremoti locali (Thurber, 1983).
    Beschreibung: Published
    Beschreibung: Palazzo Congressi della Stazione Marittima, Trieste
    Beschreibung: open
    Schlagwort(e): Tomography ; DSS ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Conference paper
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  • 97
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    Application of a new Structural Joint Inversion Approach to Teleseismic and Gravity Data from Mt.Vesuvius, Italy (2008)
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: A 3-D joint inversion of seismic and gravimetric data is performed to re-investigate the subsurface structure of Mt. Vesuvius (Italy) utilizing an improved joint inversion method. The aim is to derive models of the 3D distribution of velocity and density perturbations that are consistent with both data sets and with local velocity models. Mt. Vesuvius is a strato volcano located within a graben (Campania Plain) formed in Plio-Pleistocene. Campania Plain is bordered by mostly Mesozoic carbonaceous rocks. Mt. Vesuvius is the southernmost and the youngest of a group of Pleistocene volcanoes, three of which (Ischia, Campi Flegrei and Mt. Vesuvius) have erupted in historical times. The most recent eruption of Mt. Vesuvius occurred in 1944 and since then the volcanic activity has been characterized by moderate low magnitude seismicity and low temperature fumaroles at the summit crater. We modified the coupling mechanism between velocity and density models in the JI-3D optimized joint inversion method (Jordan and Achauer, 1999). This method was designed to provide stable and high resolution results and involves iterative optimized parameterization, 3D ray tracing, and the incorporation of a priori information. The coupling of the velocity and density models, vital to the joint inversion, is based on a cross-gradient approach (e.g. Gallardo and Meju, 2004), which has been proven to work very well in a variety of cases involving seismic, magnetic, CSEM, MT and gravity data sets. We implemented the cross-gradient coupling for our 3-D irregular adaptive grid parameterization. In contrast to conventional joint inversion methods this approach encourages structural similarities in the models and does not rely on predefined relationships between velocity and density parameters. As a consequence, the resulting velocity-density relations are not contaminated by a priori assumptions and can be utilized to derive rock physical parameters. We apply this method to data from the TomoVes project (Gasparini et al. 1998), combining seismics and Bouguer gravity and local high resolution velocity models as a priori information. The starting models for the joint inversion are derived by separate inversions of the individual data sets. We show 3D distributions of velocity perturbations and density variations from the joint inversion of teleseismic relative traveltimes and Bouguer anomaly data with the aim of extracting further information about the physical status of the volcano- tectonic system.
    Beschreibung: Published
    Beschreibung: San Francisco, CA, USA
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: open
    Schlagwort(e): joint inversion ; teleseismic data ; gravity data ; vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Poster session
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  • 98
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    Seismotomography of the crust in the transition zone between the southern Tyrrhenian and Sicilian tectonic domains (2008)
    AGU
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: A crustal tomography of seismic wave velocity was performed in the contact zone between the southern Tyrrhenian, Sicilian and Ionian tectonic units, a zone where the lithospheric structure can be expected to furnish evident signatures of dynamics related to the Tyrrhenian subduction process. A dataset of 10241 P and 5597 S readings from 932 local earthquakes recorded between 1978 and 2001 by stations operating in Sicily and Calabria was inverted by the SIMULPS12 algorithm for simultaneous computation of hypocenter parameters and Vp and Vp/Vs three dimensional distributions. The study brought significant improvement in the knowledge of the local velocity structure, furnishing new information useful to better identify the local tectonic units. The results appear to be compatible with the most recent hypotheses regarding the geodynamics of the study region.
    Beschreibung: Published
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Continental crust ; Oceanic crust ; Body wave propagation ; Evolution of the Earth: Tomography ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 99
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    Surface wave tomography in the European and Mediterranean region (2008)
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: We present a new surface-wave tomograpic study of the broad European and Mediterranean region. Our goal is to enhance the resolution of previously published group velocity models using new data from European permanent seismic networks and a dense broad-band array in Northern Apennines (RETREAT). We measure fundamental mode Rayleigh and Love wave group velocities from long period seismograms recorded at regional distance (between 600 and 7000 km). Our measurement technique is based on iterative application of multiple filters and phase-matched filters; we accurately estimate dispersion curves for more than 1500 Rayleigh wave and about 850 Love wave paths in the period range 35 s - 170 s. Consistency of measurements is evaluated by comparing ray clusters from sample earthquakes to closely spaced RETREAT stations. In the whole data set, measurement errors in group velocity decrease with increasing distance, and show to be caused by inaccuracy in the estimate of group arrival time. We calculate maps of Love and Rayleigh group velocity at selected periods by linear tomographic inversion, accounting for group arrival time errors and evaluating a posteriori group slowness errors. Data coverage in this region is not uniform, and it is highly influenced by the uneven distribution of earthquakes and seismic stations. We therefore build a laterally heterogeneous reference model by inverting a global data set of group velocity derived from the phase velocity library of Ekstrom et al., 1997. Use of this reference as an a priori model during inversion improves preliminary data coverage at the borders of our study region, and warrants consistency with global models. The implications of different regularization constraints (mathematically equivalent to norm damping or smoothing with different criteria) are analyzed and compared. Group velocity maps confirm the large scale geological lineaments known for the region: short periods maps differentiate well among thinner oceanic and thicker continental crust; the most dominant feature in long period maps is the difference between the fast Precambrian East European Platform and the low velocity signature of central Europe and western Mediterranean, separated by a sharp gradient in correspondence of the Tornquist-Tesseyre Zone. The seismically active Tethyan Belt is clearly marked by a continuous slow anomaly. Smaller scale, possibly thermally related, low velocity anomalies are found under Iceland and Mid-Atlantic Ridge, Rhine Graben and Tyrrhenian Back-Arc basin, while the Hellenic Arc is characterized by fast velocity.
    Beschreibung: SPICE EC FP6 Marie Curie RTN NERIES INFRAST-2.1-026130
    Beschreibung: Submitted
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic tomography ; Surface waves and free oscillations ; Europe ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: manuscript
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  • 100
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    Belt bending driven by lateral bending of subducting lithospheric slab: geophysical evidences from the northern Apennines (Italy) (2008)
    Elsevier
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Many of the mountain belts displaying a curved shape are "oroclines", i.e. are produced after progressive bending of an originally straight fold and thrust belt. The bending process was previously explained as a consequence of several possible events taking place in the crustal orogenic wedge, such as occurrence of obstacles, non-coaxial deformation, and mouvements on wrench faults. Recent paleomagnetic results from the northern Apenninic Arc document that this belt is properly an orocline and results from Late Messinian-Early Pliocene bending of a Messinian straight belt-foredeep system. Tomographic images in turn show the presence of a high-velocity body, interpreted as subducted slab, in the upper mantle beneath the northern Apennines, between 35 and 670 km depth. Down to 100 km, this body displays an arcuate shape which closely mirrors the geological outlines, while it appears to be straight (and parallel to the Messinian pre-rotated belt) at depth. We explore here the possibility that the arcuate shape of the northern Apennines is a consequence, closely following in time, on much deeper processes than previously suggested, i.e. the lateral bending of the subducting Adriatic plate.
    Beschreibung: Published
    Beschreibung: 53-64
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): paleomagnetism ; seismic tomography ; Northern Apennines ; orocline ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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