ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2021-09-22
    Description: We evaluate, by numerical tests, whether surface-wave attenuation can be determined from ambient-noise data. We generate synthetic recordings of numerically simulated ambient seismic noise in several experimental setups, characterized by different source distributions and different values of attenuation coefficient. We use them to verify that the source spectrum can be reconstructed from ambient recordings (provided that the density of sources and the attenuation coefficient are known) and that true attenuation can be retrieved from normalized cross correlations of synthetic signals. We then apply the so validated method to real continuous recordings from 33 broadband receivers distributed within the Colorado Plateau and Great Basin. A preliminary analysis of the signal-to-noise ratio as a function of azimuth reveals a SW-NE preferential directionality of the noise sources within the secondary microseism band (6–8s), consistent with previous studies. By nonlinear inversion of noise data we find the attenuation coefficient in the area of interest to range from ~1×10^-5 m^-1 at 0.3Hz to 4.5×10^-7 m^-1 at 0.065Hz, and confirm the statistical robustness of this estimate by means of a bootstrap analysis. The result is compatible with previous observations based on both earthquake-generated and ambient Rayleigh waves. In this regard, the method proves to be promising in accurately quantifying surface-wave attenuation at relatively high frequencies.
    Description: Published
    Description: e2020JB019865
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04.01. Earth Interior ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2021-09-21
    Description: EarthScope's USArray seismic component provided unprecedented coverage of the contiguous United States and has therefore spurred significant advances in tomographic imaging and geodynamic modelling. Here, we present a new global, radially anisotropic shear wave velocity tomography model to investigate upper mantle structure and North American Plate dynamics, with a focus on the contiguous United States. The model uses a data-adaptive mesh and traveltimes of both surface waves and body waves to constrain structure in the crust and mantle in order to arrive at a more consistent representation of the subsurface compared to what is provided by existing models. The resulting model is broadly consistent with previous global models at the largest scales, but there are substantial differences under the contiguous United States where we can achieve higher resolution. On these regional scales, the new model contains short wavelength anomalies consistent with regional models derived from USArray data alone. We use the model to explore the geometry of the subducting Farallon Slab, the presence of upper mantle high velocity anomalies, low velocity zones in the central and eastern United States and evaluate models of dynamic topography in the Cordillera. Our models indicate a single, shallowly dipping, discontinuous slab associated with the Farallon Plate, but there are remaining imaging challenges. Inferring dynamic topography from the new model captures both the long-wavelength anomalies common in global models and the short-wavelength anomalies apparent in regional models. Our model thus bridges the gap between high-resolution regional models within the proper uppermost mantle context provided by global models, which is crucial for understanding many of the fundamental questions in continental dynamics.
    Description: Published
    Description: 1730–1746
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04. Solid Earth ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2021-09-21
    Description: Passive seismic interferometry has become very popular in recent years in explorationgeophysics. However, it has not been widely applied in marine exploration. The purpose of thisstudy is to investigate the internal structure of a quasi-amagmatic portion of the Southwest IndianRidge by interferometry and to examine the performance and reliability of interferometry in marineexplorations. To reach this goal, continuous vertical component recordings from 43 ocean bottomseismometers were analyzed. The recorded signals from 200 station pairs were cross-correlated inthe frequency domain. The Bessel function method was applied to extract phase–velocity dispersioncurves from the zero crossings of the cross-correlations. An average of all the dispersion curveswas estimated in a period band 1–10 s and inverted through a conditional neighborhood algorithmwhich led to the final 1D S-wave velocity model of the crust and upper mantle. The obtained S-wavevelocity model is in good agreement with previous geological and geophysical studies in the regionand also in similar areas. We find an average crustal thickness of 7 km with a shallow layer of lowshear velocities and high Vp/Vs ratio. We infer that the uppermost 2 km are highly porous and maybe strongly serpentinized.
    Description: Published
    Description: 2811
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04.06. Seismology ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2021-09-21
    Description: Mapping variations in the attenuation of seismic energy is important for understanding dissipative mechanisms in the lithosphere, and for modeling ground shaking associated with earthquakes. We cross-correlate ambient seismic signal recorded across the EarthScope Transportable Array in the 3-15 s period range. We apply to the resulting cross correlations a new method to estimate lateral variations in Rayleigh-wave attenuation, as a function of period, beneath North America. Between 3 and 6 s, our maps are dominated by a strong eastward decrease in attenuation. This pattern vanishes at longer periods, confirming early observations based on regional earthquakes. Attenuation maps and phase-velocity maps are anti-correlated at periods between 3 and 6 s, but the anti-correlation is also largely lost at longer periods. This corresponds to the attenuation coefficient decreasing with period more rapidly in the west than in the east, while the change in phase velocity with period is more uniform across the continent. Our results point to a transition in the properties of upper-crustal materials with depth, probably related to the closure of fluid-filled cracks and pores, and imply that measures of attenuation from seismic noise carry significant information on crustal rheology.
    Description: Published
    Description: 10149
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04.01. Earth Interior ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2021-09-13
    Description: Among the geologic data, trenching records of paleoearthquakes represent an important input for the development of seismic hazard evaluations and, specifically, for the characterization of fault rupture behavior in time. Based on the available paleoseismological trenching data in the Central Apennines we have compiled a new database of surface faulting earthquakes for 10 faults. The compilation contains 109 surface faulting events, occurred in the past ~28 kyr. Events younger than 7 kyr (59 dated events) are much better constrained and, therefore, are the basis for most of the analyses. Through a quantitative multistep method, we integrate paleoseismic trench data and treat them statistically, providing relevant improvement needed for trenching-based seismic hazard evaluation. Indeed, the combined analysis of trenching data from multiple sites on the same fault led to a reduction of the approximations and uncertainties in the rupture history of individual faults. The procedure was also applied on specific fault systems and indicated that the single faults may have occasionally ruptured simultaneously, or close in time, in the past. The whole set of age ranges was also statistically analyzed to produce regional earthquake scenarios for a period much longer than the millennial historical record. The built scenarios for the last 7 kyr define a regional mean inter event time (IET) of 230-240 yr, comparable with the average recurrence time of about 200 yr, considering the number of events in time. We also identify the possible occurrence of earthquake storms, i.e., concentration of surface faulting earthquakes in the region within time periods of 200 yr, suggesting a variability in time of the seismic behavior of the faults, with alternation of peaks of activity with more “quiet” periods. Even though the paleoseismic data from the Apennines contains uncertainties, the results appear quite stable and promising for future applications in earthquake-hazard assessment.
    Description: Published
    Description: 229016
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Paleoseismology ; Statistical modeling ; Surface rupture scenarios ; Regional earthquake recurrence ; Earthquake storms ; Central Apennines ; 04.04. Geology ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2021-09-06
    Description: L'Istituto Nazionale di Geofisica e Vulcanologia (INGV) è componente del Servizio Nazionale di Protezione Civile, ex articolo 6 della legge 24 febbraio 1992 n. 225 ed è Centro di Competenza per i fenomeni sismici, vulcanici e i maremoti per il Dipartimento della Protezione Civile Nazionale (DPC). L’Osservatorio Vesuviano, Sezione di Napoli dell’INGV, ha nei suoi compiti il monitoraggio e la sorveglianza H24/7 delle aree vulcaniche attive campane (Vesuvio, Campi Flegrei e Ischia). Tali attività sono disciplinate dall’Accordo-Quadro (AQ) sottoscritto tra il DPC e l’INGV per il decennio 2012-2021 e sono dettagliate negli Allegati A e B del suddetto AQ. Il presente Rapporto sul Monitoraggio dei Vulcani Campani rappresenta l’attività svolta dall’Osservatorio Vesuviano e dalle altre Sezioni INGV impegnate nel monitoraggio dell’area vulcanica campana nel secondo semestre 2019.
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Unpublished
    Description: 4V. Processi pre-eruttivi
    Description: 6SR VULCANI – Servizi e ricerca per la società
    Description: 1IT. Reti di monitoraggio e sorveglianza
    Description: 2IT. Laboratori analitici e sperimentali
    Description: 4IT. Banche dati
    Keywords: Campi Flegrei ; Vesuvio ; Ischia ; Volcano Monitoring ; 04.06. Seismology ; 04.03. Geodesy ; 04.08. Volcanology ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2021-08-31
    Description: In this article, we present a new data collection that combines information about earthquake damage with seismic shaking. Starting from the Da.D.O. database, which provides information on the damage of individual buildings subjected to sequences of past earthquakes in Italy, we have generated ShakeMaps for all the events with magnitude greater than 5.0 that have contributed to these sequences. The sequences under examination are those of Irpinia 1980, Umbria Marche 1997, Pollino 1998, Molise 2002, L’Aquila 2009 and Emilia 2012. In this way, we were able to combine, for a total of the 117,695 buildings, the engineering parameters included in Da.D.O., but revised and reprocessed in this application, and the ground shaking data for six different variables (namely, in- tensity in MCS scale, PGA, PGV, SA at 0.3s, 1.0s and 3.0s). The potential applications of this data collection are innumerable: from recalibrating fragility curves to training machine learning models to quantifying earthquake damage. This data collection will be made available within Da.D.O., a platform of the Italian Department of Civil Protection, developed by EUCENTRE.
    Description: European project SERA – The Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe; http://www.sera-eu.org/en/home/; GA 730900.
    Description: Published
    Description: 36-51
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: N/A or not JCR
    Keywords: ShakeMap ; Damage ; Data Collection ; 05.08. Risk ; 05.02. Data dissemination ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    facet.materialart.
    Unknown
    BONONIA UNIVERSITY PRESS
    Publication Date: 2021-08-31
    Description: La sequenza sismica .del maggio 2012 ha causato diffusi fenomeni di liquefazione dei terreni, dando origine a diverse ed evidenti manifestazioni superficiali, quali fratture, lunghe anche diverse decine di metri, e fuoriuscite di sabbie e limi dal terreno su un areale piuttosto ampio. Tali effetti locali hanno assunto particolare rilevanza nei centri abitati di S. Carlo, frazione di S. Agostino, e di Mirabello, in provincia di Ferrara, dove, oltre alle evidenze sul terreno libero, hanno prodotto diffusi danneggiamenti a carico dei manufatti. Gli effetti secondari successivi alla liquefazione hanno infatti reso temporaneamente inagibili alcuni edifici, tratti di strade e reti di servizi presenti.
    Description: Published
    Description: 335-342
    Description: 4T. Sismicità dell'Italia
    Keywords: liquefazione ; emilia 2012 ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2021-08-30
    Description: The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is in charge of earthquake monitoring and surveillance in the Italian territory as a part of the civil protection sys- tem. Technological improvements in the last years were taken into account for devel- oping new protocols and software to upgrade all the procedures in the monitoring centers. Real-time earthquake evaluation consists of phase picks, preliminary and auto- matic hypocenters, local magnitudes and ground-motion parameters. The real-time analysis system presently in use at INGV is the starting point for a new multitier com- pound system that relies on four main components: an automatic earthquake detection and location system based on Earthworm; a new seismological relational database for parametric data; a full set of new webservices application programming interface spec- ifications to share information and provide data at the application level and; finally, a set of multiplatform interactive revision tools developed to analyze, store, use, and dis- tribute the seismic parameters in real time. These last three components are being com- pletely developed ex-novo at INGV in Rome. Such a system has been engineered to communicate with the International Federation of Digital Seismic Networks standard webservices as well as custom home-made INGV services. Through its custom embedded features Caravel will allow the INGV personnel on duty for seismic surveillance to evaluate and review all automatic estimations before they are communicated to the Italian civil protection agency and then published by external tools through e-mail, SMS, Twitter, and webpages.
    Description: Published
    Description: 1738–1746
    Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami
    Description: JCR Journal
    Keywords: realtime seismology, earthquake revision, web services, ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2021-07-13
    Description: The millimetre accuracy of Synthetic Aperture Radar (SAR) measurements and related multi-temporal data analyses provide fundamental information on surface displacements caused by strong earthquakes. The multi-temporal analysis of SAR interferometry data allows for the geometry, kinematics and temporal behaviour of earthquake-generating faults to be better constrained, and is being acknowledged as a promising technique in the field of earthquake precursors. We used SAR data obtained by multi-temporal interferometric techniques such as Permanent Scatterers (PS) interferometry for the investigation of pre- to post-seismic ground displacements in the region struck by theMw 6.3, 2009 L’Aquila earthquake.We analysed Europen Remote Sensing (ERS) and Envisat PS-datasets from ascending and descending orbits, and COSMO-SkyMed PS-datasets from descending orbit, collectively covering a 〉 20 year long time span. On a yearly scale, a reversal of motions that affected the hanging-wall and footwall blocks of the earthquake-generating fault is detected. In particular, the hanging-wall block is characterized by pre-seismic uplift – which we document as being independent of any hydrological control – and eastward horizontal motion for about six years, followed by subsidence and westward motion (starting six to eight months prior to the earthquake). We suggest that such a ground displacement pattern may represent an earthquake precursor signal.
    Description: Published
    Description: jgs2020-016
    Description: 2T. Deformazione crostale attiva
    Description: 7T. Variazioni delle caratteristiche crostali e "precursori"
    Description: JCR Journal
    Keywords: PsInSAR ; Earthquake Precursor ; L'Aquila earthquake ; Ground displacement ; 04.07. Tectonophysics ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...