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  • 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring  (27)
  • 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics  (26)
  • 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis  (25)
  • 04. Solid Earth::04.04. Geology::04.04.09. Structural geology  (8)
  • 04.02. Exploration geophysics
  • JSTOR Archive Collection Business II
  • Seismological Society of America  (52)
  • Istituto Nazionale di Geofisica e Vulcanologia  (17)
  • Wiley  (14)
  • American Chemical Society (ACS)
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  • 1
    Publikationsdatum: 2021-06-14
    Beschreibung: Southwestern Sicily is an area of infrequent seismic activity; however, some studies carried out in the archaeological Selinunte site suggest that, between the fourth century BC and the early Middle Ages, probably at least two earthquakes strucked this area with enough energy to damage and cause the collapse and kinematics of much of the architecture of Selinunte. Take into account that, in 2008, a noninvasive archaeological prospection and traditional data gathering methods along the Acropolis north fortifications were carried out. Following these first studies, after about 10 years, a new geophysical campaign was carried out. This second campaign benefited from the application of modern technologies for the acquisition and processing of the point cloud data on the northern part of the Acropolis, like terrestrial laser scanning and unmanned aerial vehicle photogrammetry. In this paper, we present the application of these techniques and a strategy for their integration for the 3D modelling of buildings and cultural heritages. We show how the integration of data acquired independently by these two techniques is an added value able to overcome the intrinsic limits of the individual techniques. The application to Selinunte's Acropolis allowed it to highlight and measure with high accuracy fractures, dislocation, inclinations of walls, depressions of some areas and other interesting observations, which may be important starting points for future investigations.
    Beschreibung: Published
    Beschreibung: 153-165
    Beschreibung: 2IT. Laboratori analitici e sperimentali
    Beschreibung: JCR Journal
    Schlagwort(e): 3D reconstruction ; archaeological survey ; digital elevation model ; Selinunte Archaeological Park ; terrestrial laser scanning ; unmanned aerial vehicle photogrammetry ; 05.04. Instrumentation and techniques of general interest ; 04.02. Exploration geophysics ; 05.02. Data dissemination ; 05.06. Methods
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2020-07-08
    Beschreibung: The response of continental forelands to subduction and collision is a widely investigated topic in geodynamics. The deformation occurring within a foreland shared by two opposite‐verging chains, however, is uncommon and poorly understood. The Apulia Swell in the southern end of the Adria microplate (Africa‐Europe plate boundary, central Mediterranean Sea) represents one of these cases, as it is the common foreland of the SW verging Albanides‐Hellenides and the NE verging Southern Apennines merging into the SSE verging Calabrian Arc. We investigated the internal deformation of the Apulia Swell using multiscale geophysical data: multichannel seismic profiles recording up to 12‐s two‐way time (TWT) for a consistent image of the upper crust; high‐resolution multichannel seismic profiles, high‐resolution multibeam bathymetry, and CHIRP profiles acquired by R/V OGS Explora to constrain the Quaternary geological record. The results of our analyses characterize the geometry of the South Apulia Fault System (SAFS), a 100‐km‐long and 12‐km‐wide structure attesting an extensional (and possibly transtensional) response of the foreland to the two contractional fronts. The SAFS consists of two NW‐SE right‐stepping master faults and several secondary structures. The SAFS activity spans from the Early Pleistocene through the Holocene, as testified by the bathymetric and high‐resolution seismic data, with long‐term slip rates in the range of 0.2–0.4 mm/yr. Considering the position within an area with few or none other active faults in the surroundings, the dimension, and the activity rates, the SAFS can be a candidate causative fault of the 20 February 1743, M 6.7, earthquake.
    Beschreibung: Italian Ministry for Education, University, and Research (MIUR), Premiale 2014 D. M. 291 03/05/2016.
    Beschreibung: Published
    Beschreibung: e2020TC006116
    Beschreibung: 2T. Deformazione crostale attiva
    Beschreibung: 2TR. Ricostruzione e modellazione della struttura crostale
    Beschreibung: JCR Journal
    Schlagwort(e): active tectonics ; apulia ; south apulia fault system ; 1743 earthquake ; marine geology ; stable continental region ; ionian sea ; active faults ; subsurface geology ; seismic interpretation ; 04.04. Geology ; 04.07. Tectonophysics ; 04.02. Exploration geophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2018-03-12
    Beschreibung: The paper has not any abstract
    Beschreibung: Published
    Beschreibung: 720-727
    Beschreibung: 2T. Sorgente Sismica
    Beschreibung: 1IT. Reti di monitoraggio
    Beschreibung: JCR Journal
    Schlagwort(e): Earthquake ; Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2017-04-04
    Beschreibung: On the night between May 15 and 16, 1951, two moderate earthquakes with estimated magnitudes of M 5.4 and 4.5 occurred in northern Italy, about 40 km southeast of Milan, close to the small town of Caviaga. They were recorded by several observatories worldwide, as reported by the International Seismological Summary (ISS) Bulletin. Despite the moderate magnitudes, these two events caught the attention of seismologists and have been studied in detail, in particular by Caloi et al. (1956), because they were close to Caviaga, in an area that was assumed to be aseismic. Moreover, their shallow hypocenters (ca. 5 km in Caloi et al., 1956) indicated a possible anthropogenic source, related to wells for gas withdrawal. In the absence of any further discussion or revision of the original study by Caloi et al. (1956), the Caviaga earthquakes have been included in several compilations of induced seismicity, and they have been generally accepted as cases of anthropogenic events. After 60 years it is possible to revisit this interpretation using improved computational techniques, the available high-resolution data, enriched historical catalogs, and a deeper understanding of the regional seismotectonic and crustal structure. The focus of this study is the relocation of these two events with the use of modern hypocentral location methods, and the analysis of the historical seismicity of the area. A complete seismic source parameterization is out of the scope of this preliminary study. In the following we describe the regional geological setting and the gas reservoir characterization, introduce the context of historical seismicity, provide a description of the main shock relocation, discuss the uncertainties of the hypocentral parameters and estimate the variation of the stress field in proximity to wells. We consider this revision necessary to be able to discuss the possibility that these two events were not induced by human activity, as well as to improve the quality of the dataset for decision makers involved in risk evaluation.
    Beschreibung: Published
    Beschreibung: 1335-1344
    Beschreibung: 6T. Sismicità indotta e caratterizzazione sismica dei sistemi naturali
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Induced Seismicity ; Seismic analysis ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2021-12-16
    Beschreibung: We reconstruct the tectonic framework of the 24 August 2016, Amatrice earthquake. At least three main faults, including an older thrust fault (Sibillini Thrust), played an active role in the sequence. The mainshock nucleated and propagated along an extensional fault located in the footwall of the Sibillini Thrust, but due to the preliminary nature of the data the role of this thrust is still unclear. We illustrate two competing solutions: 1) the coseismic rupture started along an extensional fault and then partially used the thrust plane in extensional motion; 2) the thrust fault acted as an upper barrier to the propagation of the mainshock rupture, but was partially reactivated during the aftershock sequence. In both cases our tectonic reconstruction suggests an active role of the thrust fault, providing yet another example of how structures inherited from older tectonic phases may control the mainshock ruptures and the long-term evolution of younger seismogenic faults.
    Beschreibung: Published
    Beschreibung: 1-10
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): 2016 Amatrice earthquake ; Sibillini thrust ; normal faulting ; extensional reactivation ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2021-03-04
    Beschreibung: Macroseismic investigation with data collected through web- based questionnaires is today routinely applied by most impor- tant seismological institutions, such as the U.S. Geological Survey (http://earthquake.usgs.gov/earthquakes/dyfi/; last accessed December 2014), British Geological Survey (http://www. earthquakes.bgs.ac.uk/questionnaire/EqQuestIntro.html; last accessed December 2014), European-Mediterranean Seismological Centre (http://www.emsc-csem.org/Earthquake/Contribute/ choose_earthquake.php?lang=en; last accessed December 2014), Schweizerische Erdbebendienst (http://www.seismo.ethz. ch/eq/detected/eq_form/index_EN; last accessed December 2014), Bureau Central Sismologique Français (http://www .seisme.prd.fr/english.php; last accessed December 2014), and the New Zealand GeoNet project (http://www.geonet.org.nz/ quakes/; last accessed December 2014). The wide diffusion of Internet and the citizen collaboration (crowdsourcing) allow documentation of information on seismic effects and production of a macroseismic field with low costs and almost in real time. Transformation from qualitative information (as given by ques- tionnaires) to numerical quantification is a crucial issue. In the traditional evaluation of intensity, experts used to work through a complex comparison of effects basically driven by personal expe- rience. The major problem with this approach concerns the dif- ficulty in verifing and reproducing the evaluation process due to the lack of a detailed explanation of the employed workflow and to the large variability of possible cases. On the other hand, an automatic method for the estimation of macroseismic intensities needs to be completely well defined and specified in order to be reproducible and verifiable. For these reasons, this paper presents a comprehensive explanation of our intensity assessment method. A useful automatic method for intensity assessment should be computationally fast and strictly follow the macroseismic scales. To meet these requirements in 2010, we proposed a method that firstly quantified the effects using additive scores associated with each answer of the questionnaire item and then determined an intensity estimate for each questionnaire (Sbarra et al., 2010). After a trial period and having collected more than 500,000 questionnaires, we were able to thoroughly test the method. As a result of this testing, we describe here a new improved method that takes into account further factors, such as the situation and the location of the observer (Sbarra et al., 2012, 2014), to obtain a more accurate estimate of the macroseismic intensity degree at the municipality level. In this paper, we show some applications of our method with reference to the Mercalli–Cancani–Sieberg (MCS) scale, because this scale has long been used with Italian earthquakes and allows easy comparison between these intensities and other traditional ones.
    Beschreibung: Published
    Beschreibung: 985-990
    Beschreibung: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Beschreibung: 5T. Sorveglianza sismica e operatività post-terremoto
    Beschreibung: 4IT. Banche dati
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Macroseismics ; intensity ; questionnaires ; attenuation ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2021-03-02
    Beschreibung: On 30 October 1930, an Mw 5.8 earthquake hit the northern Marche coastal area (central Italy), causing significant damage (I0 VIII–IX degree Mercalli–Cancani– Sieberg) along a 40 km stretch of the Adriatic coast between Pesaro and Ancona, centered on the town of Senigallia. This area is characterized by relatively infrequent and moderate-sized earthquakes and by elusive active faults. In spite of the presence of wellknown northwest–southeast-trending, northeast-verging fault-propagation folds forming the outer thrusts of the Apennines, the current level of activity, and the kinematics of these coastal structures are still controversial. We present a multidisciplinary analysis of the source of the 30 October 1930 Senigallia earthquake, combining instrumental and macroseismic data and elaborations with available evidence from geological and tectonic investigations.We determine the main seismic parameters of the source, including the earthquake location, its magnitude, and, for the first time, its focal mechanism, providing the first instrumental evidence for thrust faulting along the northern Marche coastal belt. Our findings provide conclusive evidence for the current activity of the northern Marche coastal thrusts. As such they have significant implications for the seismic hazard of the area, a densely populated region that hosts historical heritage, tourism facilities, industrial districts, and key transportation infrastructures.
    Beschreibung: Published
    Beschreibung: 1548-1561
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 1930 Senigallia earthquake ; seismogenic source ; Northern Marche ; Thrust fault ; Focal mechanism ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2021-03-04
    Beschreibung: We investigate the influence of building height on the ability of people to feel earthquakes and observe that, in an urban area, short and tall buildings reach different levels of excitation. We quantify this behavior by analyzing macroseismic reports collected from individuals through the Internet, focusing on transitory effects, therefore in the elastic regime during recent earthquakes in Italy in the local magnitude (ML) range of 3 to 5.9. We find a maximum difference of 0.6 intensity units between the top floors of tall (7–10 stories) and short (1–2 stories) buildings at the highest considered magnitudes. As expected, tall buildings experience greater shaking than short buildings during large earthquakes at large source distances. However, we observe the opposite behavior at close distances when the ML is less than 3.5. These results can be explained by considering the different spectra radiated by small and large earthquakes and the different fundamental mode resonances of buildings (i.e., shorter buildings have higher resonance frequencies and vice versa). Using idealized building models excited by real acceleration time histories, we compute synthetic accelerograms on the top floors of short and tall buildings, and confirm the trend of the observed differences in felt intensities.
    Beschreibung: Published
    Beschreibung: 1803-1809
    Beschreibung: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Macroseismics ; intensity ; building height ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2017-04-04
    Beschreibung: The destructive earthquake (M 7) that struck western Calabria (southern Italy) on 8 September 1905 profoundly hit a broad region, also generating a feeble tsunami. For all the damage it caused, this event was as much studied as not fully explained. Literature source models are numerous and diverse, in fault geometry, location, and associated magnitude. They also differ in nature, since these solutions are either field- based, or deriving from tsunami modeling, and macroseismic data inversion. Most. Neither all of these literature source models are not consistent with the damage pattern caused by the 1905 earthquake. To contribute to the identification of the seismogenic source of this destructive event, we performed a series of ground shaking scenarios, based on different faults that various authors associated with this event. The only documented data available suitable for our comparative purposes are the macroseismic intensities associated with localities affected by the event. We transformed the values of ground motion we computed for the same datapoints into intensities. We then attributed a quantitative fit to each modeled seismogenic source, evaluated with the quadratic sum of residuals between observed and calculated intensities. Our results show that two out of 7 literature source models are compatible with the damage distribution caused by the 1905 earthquake. The different parameters and boundary conditions constraining these two solutions suggest that either seismogenic source should include further complexities. Alternatively, since these two sources are antithetic and partially form a graben, they might have kinematically interacted, if passively, on 8 September 1905.
    Beschreibung: Project ISTEGE: “Indagine Sismotettonica del TErremoto dell'8 Settembre 1905 (Mw 7.4) nel Golfo di Sant'Eufemia – offshore tirrenico calabrese”, supported by OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale); Project RITMARE, funded by Dipartimento della Protezione Civile (Italy's National Civil Protection).
    Beschreibung: Published
    Beschreibung: 912-927
    Beschreibung: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Shaking scenarios ; Seismogenic sources ; 1905 earthquake ; Southern Italy ; 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::04.06.11. Seismic risk ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2017-04-04
    Beschreibung: We propose a Bayesian approach for the determination of the stress field from focal mechanism datasets. This method is a revision of the right trihedra method (RTM), used for both fault striation and focal mechanism data. The new probabilistic formulation of the RTM method (BRTM) allows a quantitative estimation of the confidence regions for the principal stress axes. Using an appropriate graphical representation, the method is able to provide simultaneous information about the stress field and its reliability.
    Beschreibung: Published
    Beschreibung: 968-977
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Beschreibung: 5V. Sorveglianza vulcanica ed emergenze
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): stress inversion ; focal mechanisms ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Publikationsdatum: 2017-04-04
    Beschreibung: Mt. Vesuvius (southern Italy) is one of the most hazardous volcanoes in the world. Its activity is currently characterized by moderate seismicity, with hypocenters located beneath the crater zone with depth rarely exceeding 5 km and magnitudes generally less than 3. The current configu- ration of the seismic monitoring network of Mt. Vesuvius consists of 18 seismic stations and 7 infrasound microphones. During the period 2006- 2010 a seismic array with 48 channels was also operative. The station distribution provides appropriate coverage of the area around the volcanic edifice. The current development of the network and its geometry, under conditions of low seismic noise, allows locating seismic events with M〈1. Remote instruments continuously transmit data to the main acquisition center in Naples. Data transmission is realized using different technological solutions based on UHF, Wi-Fi radio links, and TCP/IP client-server applications. Data are collected in the monitoring center of the Osservatorio Vesuviano (Italian National Institute of Geophysics and Volcanology, Naples section), which is equipped with systems for displaying and analyzing signals, using both real-time automatic and manual procedures. 24-hour surveillance allows to immediately communicate any significant anomaly to the Civil Protection authorities.
    Beschreibung: Published
    Beschreibung: S0450
    Beschreibung: 5V. Sorveglianza vulcanica ed emergenze
    Beschreibung: 1IT. Reti di monitoraggio e Osservazioni
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Vesuvius ; seismic network ; volcano monitoring ; network performance ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: The energy flux F at the rupture tip has been previously computed only for 2D steady-state singular cracks. In this paper, I compute F for fully dynamic 3D ruptures, propagating both with constant and variable rupture speed (v_r) over finite faults directed by a governing law with a cohesive zone (and thus nonsingular ruptures). The results presented here indicate that F is positive and increasing over the whole range of v_r from zero up to P-wave speed. This is in contrast with 2D steady-state singular cracks, which predict the existence of a forbidden zone in the range of rupture speeds because in that interval F would be negative. Moreover, I found that in 3D ruptures with cohesive force, F is proportional to v_r, again in contrast to 2D steady-state singular cracks, in which F is not a unique function of v_r and also exhibits an inverse dependence on v_r. More specifically, it emerges that fast earthquakes tend to have a higher energy flux at the crack tip compared with slow ruptures. Finally, I show that the magnitude of F is basically due to its component aligned in the direction of the initial shear stress.
    Beschreibung: Published
    Beschreibung: 2670-2679
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Coseismic ruptures ; Energy flux ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 13
    Publikationsdatum: 2017-04-04
    Beschreibung: In 2012 two seismic surveys were carried out in the area of Bagnolifutura (Campi Flegrei, Naples), with the aim of characterizing the properties of the seismic noise during the drilling activity performed in the framework of the Campi Flegrei Deep Drilling Project (CFDDP; https://sites.google.com/site/cfddpproject/). During the first survey, which was conducted from 2 to 4 April, before the drilling, seven broadband three-component seismometers were installed in two different array configurations. The second survey started on November 26, in concomitance with the drilling operations and fluid injection, and ended on December 5, four days after the end of the drilling, when the maximum depth of 502 m was reached. During this period seven broadband and one short-period three-component sensors were installed. A preliminary spectral analysis was performed on samples of seismic noise; moreover the root mean square of the amplitude of the signals and the polarization parameters were calculated. The preliminary results show similar spectral and polarization features for the data of the two surveys, whereas the amplitude of the seismic noise collected during the second survey is greatly influenced by the bad meteorological conditions. As future development experimental site transfer functions from Nakamura’s technique and surface wave dispersion from array techniques will be calculated to obtain the shallow crustal structure. The results corresponding to the different phases of the drilling activity will be compared, with the aim of establishing if significant variations of the medium properties have occurred during the experiment. Moreover the recorded signals will be deeply investigated in order to detect the eventual occurrence of microseismicity induced by fluid injection and to define its features.
    Beschreibung: Published
    Beschreibung: 1-18
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Campi Flegrei ; seismic noise ; array techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: We studied the ambient noise recorded at Irpinia Seismic Network (ISNet), a seismic network installed along the Campania–Lucania Apenninic chain (southern Italy), with the aim of characterizing the noise spectrum for each station as a function of time and the detection threshold of the network. For the latter purpose, we proposed a mixed indirect approach based on the signal-to-noise ratio (SNR) in the time domain, with parameterization in the frequency domain. The source signature is represented by the convolution of the Brune source time function with the Azimi attenuation curve. We found that 1.3 is the minimum magnitude an event should have to be detected at least at five stations with an SNR larger than five, wherever it occurs. We observed a space variability of the detection threshold as large as 0.3 units, ascribed to both the geometrical configuration of the network and the differences in the noise levels at the different stations. A sensitivity study indicates that the estima- tion of the detection threshold is robust for changes in the focal depths and stress drop, while it is strongly affected by the anelastic attenuation. In our case, changes of the reduced time t␣ in the range 0.015–0.035 s generate changes in the completeness threshold of 0.5 units. Noise levels were obtained by a statistical analysis on the power spectral density curves along almost three years of continuous data from 22 stations. We found that, at short periods, major time variations are generated by diurnal changes in the wind intensity and other meteorological factors. At longer periods, we retrieved the micro- seismic peak, resulting from the constructive interference of oceanic waves. We also found an additional peak between 2 and 4 s, correlated with the sea wave height along the Tyrrhenian coast.
    Beschreibung: Published
    Beschreibung: 574–586
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): seismic noise, seismic network, detection threshold, local events, power spectral density, seismic source ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Publikationsdatum: 2017-04-04
    Beschreibung: On May 20th, 2012, an ML 5.9 earthquake (Table 1) occurred near the town of Finale Emilia, in the Central Po Plain, Northern Italy (Figure 1). The mainshock caused 7 casualties and the collapse of several historical buildings and industrial sheds. The earthquake sequence continued with diminishing aftershock magnitudes until May 29th, when an ML 5.8 earthquake occurred near the town of Mirandola, ~12 km WSW of the mainshock (Scognamiglio et al., 2012). This second mainshock started a new aftershock sequence in this area, and increased structural damage and collapses, causing 19 more casualties and increasing to 15.000 the number of evacuees. Shortly after the first mainshock, the Department of Civil Protection (DPC) activated the Italian Space Agency (ASI), which provided post-seismic SAR Interferometry data coverage with all 4 COSMO-SkyMed SAR satellites. Within the next two weeks, several SAR Interferometry (InSAR) image pairs were processed by the INGV-SIGRIS system (Salvi et al., 2012), to generate displacement maps and preliminary source models for the emergency management. These results included continuous GPS site displacement data, from private and public sources, located in and around the epicentral area. In this paper we present the results of the geodetic data modeling, identifying two main fault planes for the Emilia seismic sequence and computing the corresponding slip distributions. We discuss the implication of this seismic sequence on the activity of the frontal part of the Northern Apennine accretionary wedge by comparing the co-seismic data with the long term (geological) and present day (GPS) velocity fields.
    Beschreibung: Published
    Beschreibung: 645-655
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: 1.9. Rete GPS nazionale
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Earthquake ; CFF analysis ; Tectonic ; geodynamic ; Seismic source ; Northern apennine (Italy) ; 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::04.06. 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::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    Publikationsdatum: 2017-04-04
    Beschreibung: In the present paper, we will describe the field survey (Fig. 1) and the data analysis of an experiment carried out to put constraints on the magnitude detection threshold in the area of Campi Flegrei. Results show that seismic radiation emitted from VT seismic events at frequency lower than 2 Hz has a high detection threshold (minimum magnitude around 1.5). In the range between 2 and 20 Hz, VT events with magnitudes smaller than about 0.5 have a high probability to be undetected. This result indicates that noise reduction through borehole stations and/or small arrays is essential for an accurate seismic monitoring in the Campi Flegrei area.
    Beschreibung: Published
    Beschreibung: 190-198
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): seismic noise ; magnitude detection ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 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
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Publikationsdatum: 2017-04-04
    Beschreibung: On 20 May 2012, at 02:03:52 GMT, an earthquake with Mw 6.1 (RCMT, http://www.bo.ingv.it/RCMT) occurred in northern Italy striking a densely populated area. The mainshock was followed a few hours later by two severe aftershocks having the same local magnitude (Ml 5.1, 1 and 2 in Figure 1a), and by hundreds of smaller aftershocks. Nine days later, on 29 May, at 07:00:03 GMT, a second event with moment magnitude Mw 6.0 (RCMT, http://www.bo.ingv.it/RCMT) occurred to the west, on an adjacent fault segment. This event was also followed by hundreds of aftershocks, three of them having local magnitude 5.3, 5.2 and 5.1 (3, 4 and 5, respectively, in Figure 1a) (locations from Istituto Nazionale di Geofisica e Vulcanologia, hereinafter INGV, http://iside.rm.ingv.it/; Malagnini et al., 2012; Scognamiglio et al., 2012). Despite the moderate number of casualties if compared to other major events in the Italian history, the economic loss was extremely high, resulting in about EUR 5 billion (AON Benfield, 2012, http://www.aon.com/), as the majority of Italian industrial activities and infrastructures concentrate in this area, the eastern Po plain, which is the largest sedimentary basin in Italy. The mainshocks are associated to two thrust faults with an approximate E-W trend dipping to the South (Figure 1b). The majority of the faults in this region are located in the upper crust, at depths lower than 10 km. The two main shocks are among the strongest earthquakes generated by thrust faults ever recorded in Italy in the instrumental era. The Emilia sequence has been extensively recorded by several strong-motion networks, operating in the Italian territory and neighbouring countries. Some of the networks acquire continuous data streams at their national data centres, which are nodes of EIDA (European Integrated Data Archive, hhtp://eida.rm.ingv.it), a federation of several archives, so that the waveforms can be obtained immediately after the occurrence of an event. Other networks, such as the Italian accelerometric network (RAN), managed by the Italian Department of the Civil Protection (hereinafter DPC), distribute the acceleration waveforms through their web site (http://protezionecivile.gov.it). The data set explored in this study is relative to the six events of the sequence having Ml 〉 5 (Table 1) and consists in 365 accelerograms recorded within a distance of 200 km from the epicentres, that were provided by the permanent and temporary seismic networks of INGV, the Swiss Seismological Service (SED, http://www.seismo.ethz.ch/index) and the DPC.
    Beschreibung: Published
    Beschreibung: 629-644
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Strong motion ; May-June 2012 Emilia Romagna earthquake sequence ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Publikationsdatum: 2017-04-04
    Beschreibung: In the 1980's, from an analysis of satellite images, Russian scientists reported on a short-term thermal infrared radiation enhancement that occurred before some medium-to-large earthquakes in central Asia [Gorny et al. 1988]. Since then, many researchers have been studying earthquake thermal anomalies with satellite remote sensing data [Qiang et al. 1991, Tronin 1996, Tramutoli et al. 2001, Ouzounov and Freund 2004, Saraf and Choudhury 2004, Aliano et al. 2008, Blackett et al. 2011]. Recently, abnormal surface latent heat flux [Dey and Singh 2003, Cervone et al. 2005, Qin et al. 2009, Qin et al. 2011, Qin et al. 2012], outgoing long-wave radiation [Ouzounov et al. 2007] and microwave radiation [Takashi and Tadashi 2010] have also been shown to precede earthquakes. To investigate the possible physical mechanisms of such satellite thermal anomalies, some studies conducted a series of detecting experiments on rock loaded to fracturing [Wu et al. 2000, Freund 2002, Wu et al. 2002, Wu et al. 2006a, Wu et al. 2006b, Freund et al. 2007], and some hypotheses have been proposed. These have included: leaking of pore-gas, and hence the resulting greenhouse effect [Qiang et al. 1995]; activating and recombining of p-holes during rock deformation [Freund 2002]; release of latent heat due to near-surface air ionization [Pulinets et al. 2006], and stress-induced thermal effects due to friction and fluids [Wu and Liu 2009]. According to the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology), two major earthquakes with almost the same large magnitudes struck northern Italy, on the Po Plain in the Emilia Region. The first hit on May 20, 2012, at 02:03 UTC, with ML 5.9 (44.89 °N, 11.23 °E; 6 km in depth), and the second on May 29, 2012, at 07:00 UTC, with ML 5.8 (44.85 °N, 11.09 °E; 10 km in depth). These caused a total of 27 deaths and widespread damage. In this study, the long-term temperature data from both satellite and ground (with greater emphasis on the satellite data) have been used to determine whether there were thermal anomalies associated with this Emilia 2012 seismic sequence. In particular, the next section will be dedicated to describing both the data and the method of analysis. In Section 3, we provide the more significant results, which we discuss in Section 4, together with the main conclusions. We acknowledge that this work cannot be exhaustive, as it will require more data and analyses. However, although further studies will be welcome, we are confident that we have done the best with the data at our disposal.
    Beschreibung: Published
    Beschreibung: 823-828
    Beschreibung: 1.10. TTC - Telerilevamento
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): earthquake event ; numerical method ; surface temperature ; Emilia-Romagna, Italy ; Emilia ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 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::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    facet.materialart.
    Unbekannt
    Istituto Nazionale di Geofisica e Vulcanologia
    Publikationsdatum: 2021-03-01
    Beschreibung: On September 6, 2002, at 01:21 GMT, the western part of the Tyrrhenian coast of Sicily was hit by an earthquake of magnitude ML = 5.6, representing the mainshock of a seismic sequence of roughly 500 earthquakes recorded in about one month. The event, although characterized by a moderate magnitude and located some forty kilometres offshore, produced relevant macroseismic effects in the Palermo area. A macroseismic survey was carried out soon after the earthquake with the aim of defining, for Civil Protection purposes, the damage scenario over a territory which is densely urbanised. In all, 134 localities were investigated. Damage generally depended on the high vulnerability of the buildings both for problems related to the old age - as is the case of the Palermo historical centre - and for peculiar unfavourable conditions due to site effects, particularly in some quarters of the city and in the nearby locality of Ficarazzi. Damage to masonry consisted of falling plaster, failure of corner walls, diagonal cracks in walls and widening of previous fissures. Some degraded buildings, almost abandoned and with evident lack of maintenance, suffered partial structural failure of roofs and floors. As regards reinforced concrete (RC) frame buildings, several edifices with 5-10 storeys suffered cracks in partitions and infill walls, sometimes with failure of these elements, and falling plaster. Fine cracks in beams of frames have also been observed, but without determining significant structural problems. In general, damage affects the lowest storeys of the RC frame buildings. According to the European Macroseismic Scale 1998, the maximum value of intensity, 6, was assigned to Palermo and Ficarazzi. The earthquake has also provoked effects on natural surroundings. Two types of phenomena have been detected: (i) hydrological effects and (ii) slope instability processes. The most relevant was the landslide which occurred near the village of Cerda, 60 km from the epicentre.
    Beschreibung: Published
    Beschreibung: 1-15
    Beschreibung: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Palermo ; terremoto 2002 ; macrosismica ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Publikationsdatum: 2021-03-01
    Beschreibung: Il presente lavoro è costituito dalla raccolta sistematica delle indagini macrosismiche eseguite in occasione dei terremoti di maggior rilievo verificatisi in Sicilia orientale e Calabria meridionale dal Gennaio 1999 al Gennaio 2001. I rilievi precedenti al Settembre 1999 sono stati effettuati nell’ambito delle attività del Gruppo Nazionale per la Difesa dai Terremoti, svolte presso l’Istituto Internazionale di Vulcanologia – CNR di Catania. Successivamente a tale data le indagini macrosismiche hanno costituito parte integrante delle attività di monitoraggio del Sistema Poseidon. Entrambi gli enti adesso costituiscono la sezione di Catania dell’Istituto Nazionale di Geofisica e Vulcanologia.
    Beschreibung: Published
    Beschreibung: 1-59
    Beschreibung: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Sicilia ; terremoti ; macrosismica ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Publikationsdatum: 2017-04-04
    Beschreibung: We present the first application of a time reverse location method in a volcanic setting, for a family of long-period (LP) events recorded on Mt Etna. Results are compared with locations determined using a full moment tensor grid search inversion and cross-correlation method. From 2008 June 18 to July 3, 50 broad-band seismic stations were deployed on Mt Etna, Italy, in close proximity to the summit. Two families of LP events were detected with dominant spectral peaks around 0.9 Hz. The large number of stations close to the summit allowed us to locate all events in both families using a time reversal location method. The method involves taking the seismic signal, reversing it in time, and using it as a seismic source in a numerical seismic wave simulator where the reversed signals propagate through the numerical model, interfere constructively and destructively, and focus on the original source location. The source location is the computational cell with the largest displacement magnitude at the time of maximum energy current density inside the grid. Before we located the two LP families we first applied the method to two synthetic data sets and found a good fit between the time reverse location and true synthetic location for a known velocity model. The time reverse location results of the two families show a shallow seismic region close to the summit in agreement with the locations using a moment tensor full waveform inversion method and a cross-correlation location method.
    Beschreibung: Published
    Beschreibung: 452-462
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Volcano seismology ; Computational seismology ; Wave propagation ; 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
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    Publikationsdatum: 2017-04-04
    Beschreibung: After the 1976 Friuli earthquake (Ms = 6.5) in north-eastern Italy that caused about 1,000 casualties and widespread destruction in the Friuli area, the Italian government established the Centro di Ricerche Sismologiche (CRS). This is now a department of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), and it is specifically devoted to the monitoring of the seismicity of north-eastern Italy. Since its inception, the North-East Italy Seismic Network has grown enormously. Currently, it consists of 14 broad-band and 20 short-period seismic stations, all of which are telemetered to and acquired in real time at the OGS-CRS data center in Udine. Data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of 94 seismic stations acquired in real time, which confirms that the OGS is the reference institute for seismic monitoring of north-eastern Italy. Since 2002, CRS has been using the Antelope software suite as the main tool for collecting, analyzing, archiving and exchanging seismic data. SeisComP is also used as a real-time data exchange server tool. A customized web accessible server is used to manually relocate earthquakes, and automatic procedures have been set-up for moment-tensor determination, shaking-map computation, web publishing of earthquake parametric data, waveform drumplots, state-of-health parameters, and quality checks of the station by spectra analysis. Scripts for email/SMS/fax alerting to public institutions have also been customized. Recently, a real-time seismology website was designed and set-up (http://rts.crs.inogs.it/).
    Beschreibung: Istituto Nazionale di Geofisica e Vulcanologia
    Beschreibung: Published
    Beschreibung: 67-75
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Seismological Research Center ; OGS ; acquiring seismic data ; archiving seismic data ; analyzing seismic data ; exchanging seismic data ; real time ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Publikationsdatum: 2017-04-04
    Beschreibung: In this paper we investigate nature and properties of narrow-band, transient seismic signals observed by a temporary array deployed in the Val Tiberina area (central Apennines, Italy). These signals are characterized by spindle-shaped, harmonic waveforms with no clear S-wave arrivals. The first portion of the seismograms exhibits a main frequency peak centred at 4.5 Hz, while the spectrum of the slowly decaying coda is peaked at about 2 Hz. Events discrimination is performed using a matched-filtering technique, resulting in a set of 2466 detections spanning the 2010 January–March time interval. From a plane-wave-fitting procedure, we estimate the kinematic properties of signals pertaining to a cluster of similar events. The repetition of measurements over a large number of precisely aligned seismograms allows for obtaining a robust statistics of horizontal slownesses and propagation azimuths associated with the early portion of the waveforms. The P-wave arrival exhibits horizontal slownesses around 0.1 s km−1, thus suggesting waves impinging at the array almost vertically. Separately, we use traveltimes measured at a sparse network to derive independent constraints on epicentral location. Ray parameters and azimuths are calibrated using slowness measurements from a local, well-located earthquake. After this correction, the joint solution from traveltime inversion and array analysis indicates a source region spanning the 1–3 km depth interval. Considerations related to the source depth and energy, and the occurrence rate which is not related to the daily and weekly working cycles, play against a surface, artificial source. Instead, the close resemblance of these signals to those commonly observed in volcanic environments suggest a source mechanism related to the resonance of a fluid–filled fracture, likely associated with instabilities in the flux of pressurized CO2.
    Beschreibung: Published
    Beschreibung: 918-928
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Fracture and flow ; Earthquake source observations ; Interface waves ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Publikationsdatum: 2017-04-04
    Beschreibung: Paper introducing and describing the EGU2010 SM1.3 session, "Seismic Centers Data Acquisition" (http://meetingorganizer.copernicus.org/EGU2010/session/2427)
    Beschreibung: Session «SM1.3 – Seismic Centers Data Acquisition» at the General Assembly 2010 of the European Geosciences Union (EGU), taking place in Vienna (Austria) between 2–7 May 2010, was organized to present both differences and similarities in operations by different types of seismic data centers in order to share experiences and stimulate constructive discussions. Only a few, widely used, "all-in-one" data acquisition and processing packages are available for seismic data centers, two public domain tools (SeisComP and EarthWorm) and one commercial tool (Antelope). The choice for any particular tool may depend on many different criteria, from operational aspects to scientific results, or on the availability of specific requirements in relation to a specific mission. The development of EarthWorm originally started in 1993 in the USA to replace aging and vendor tied regional processing systems. Antelope, on the other hand, started around 1996 with the aim to have real-time data flow from the field sensors to the scientist. SeisComP also started in the nineties as real-time data acquisition and processing system and evolved initially towards an early warning system for seismic observatories. Protocols have been established to exchange real-time waveform data between the different packages.
    Beschreibung: Istituto Nazionale di Geofisica e Vulcanologia
    Beschreibung: Published
    Beschreibung: 1-7
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): EGU2010 ; Seismic Centers ; Data Acquisition ; Antelope ; SeisComP ; EarthWorm ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Publikationsdatum: 2017-04-04
    Beschreibung: A seguito dei tre eventi sismici di magnitudo ≥ 4.0, che tra il 10 e il 12 gennaio 2010 hanno colpito la zona del Fermano-Maceratese (Italia centrale), sono state installate due stazioni della rete sismica temporanea dell’INGV ad integrazione delle reti permanenti, nazionale e regionale, già presenti nell’area.
Questa zona ha una sismicità particolare confinata in uno strato sismogenetico fragile ad una profondità compresa tra 15 e 25 km meritevole di un’analisi dettagliata. Le stazioni sono state collegate in tempo reale al centro di acquisizione della Rete Sismica Nazionale dell’INGV utilizzando dei router UMTS. Questa soluzione si è rivelata estremamente rapida e conveniente. Solo una delle stazioni ha infatti risentito della debolezza del segnale UMTS, ma in generale i dati raccolti hanno contribuito a migliorare le localizzazioni ipocentrali prodotte in tempo reale presso la sala di sorveglianza sismica di Roma. L’integrazione dei dati acquisiti dalle stazioni temporanee ai dati prodotti dalle reti permanenti, ha fornito un dataset di buona qualità già rielaborato per degli studi di dettaglio dell’area.
    Beschreibung: Published
    Beschreibung: 1-30
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Emergency ; Seismic Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    facet.materialart.
    Unbekannt
    Istituto Nazionale di Geofisica e Vulcanologia
    Publikationsdatum: 2017-04-04
    Beschreibung: A Mw 3.9 foreshock on May 19, 2012, at 23:13 UTC, was followed at 02:03 on May 20, 2012, by a Mw 5.9 earthquake that hit a densely populated area in the Po Plain, west of the city of Ferrara, Italy (Figure 1). Over the subsequent 13 days, six Mw 〉5 events occurred; of these, the most energetic was a Mw 5.8 earthquake on May 29, 2012, 12 km WSW of the main shock. The tragic balance of this sequence was 17 casualties, hundreds of injured, and severe damage to the historical and cultural heritage of the area. From a seismological point of view, the 2012 earthquake was not an outstanding event in its regional context. The same area was hit in 1996 by a Mw 5.4 earthquake [Selvaggi et al. 2001], and previously in 1986 and in 1967 (DBMI11) [Locati et al. 2011]. The most destructive historical event was the 1570, Imax 8 event, which struck the town of Ferrara [Guidoboni et al. 2007, Rovida et al. 2011]. The 2012 seismic sequence lasted for several weeks and probably developed on a well-known buried thrust fault [Basili et al. 2008, Toscani et al. 2009, DISS Working Group 2010], at depths between 2 km and 10-12 km.
    Beschreibung: Published
    Beschreibung: 569-573
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Empirical Green's functions ; Array analysis ; Earthquake source dynamics ; 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
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Publikationsdatum: 2017-04-04
    Beschreibung: We present a collection of pictures of the coseismic secondary geological effects produced on the environment by the 2012 Emilia seismic sequence in northern Italy. The May-June 2012 sequence struck a broad area located in the Po Plain region, causing 26 deaths and hundreds of injured, 15.000 homeless, severe damage of historical centres and industrial areas, and an estimated economic toll of ~2 billion of euros. The sequence included two mainshocks (Figure 1): the first one, with ML 5.9, occurred on May 20 between Finale Emilia, S. Felice sul Panaro and S. Martino Spino; the second one, with ML 5.8, occurred 12 km southwest of the previous mainshock on May 29. Both the mainshocks occurred on about E-W trending, S dipping blind thrust faults; the whole aftershocks area extends in an E-W direction for more than 50 km and includes five ML≥5.0 events and more than 1800 ML〉1.5 events. Ground cracks and liquefactions were certainly the most relevant coseismic geological effects observed during the Emilia sequence. In particular, extensive liquefaction was observed over an area of ~1200 km2 following the May 20 and May 29 events. We collected all the coseismic geological evidence through field survey, helicopter and powered hang-glider trike survey, and reports from local people directly checked in the field. On the basis of their morphologic and structural characteristics the 1362 effects surveyed were grouped into three main categories: a) liquefactions related to overpressure of aquifers, occurring through several aligned vents forming coalescent flat cones (485 effects); b) liquefactions with huge amounts of liquefied sand and fine sand ejected from fractures tens of meters long (768); c) extensional fractures with small vertical throws, apparently organized in an en-echelon pattern, with no effects of liquefaction (109). The photographic dataset consists of 99 pictures of coseismic geological effects observed in 17 localities concentrated in the epicentral area. The pictures are sorted and presented by locality of observation; each photo reports several information such as the name of the site, the geographical coordinates and the type of effect observed. Figure 1 shows a map of the pictures sites along with the location of the two mainshocks; Figure 2 shows a detail of the distribution of the liquefactions in the area of S. Carlo. The complete description of the coseismic geological effects induced by the Emilia sequence, their relation with the aftershock area, the InSAR deformation area and the I〉6 EMS felt area, along with the description of the technologies used for data sourcing and processing are shown in Emergeo Working Group [2012a and 2012b].
    Beschreibung: Published
    Beschreibung: 1-70
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): liquefaction features ; 2012 Emilia seismic sequence ; survey report ; EMERGEO ; 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::04.04.08. 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
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 28
    Publikationsdatum: 2017-04-04
    Beschreibung: In the northern Apennines, the Palaeozoic basement involved in the Late Oligocene–Middle Miocene nappe stack contains metamorphic units for which hypothetical ages have been assigned on the basis of lithological correlations with the Palaeozoic formations of the Variscan chain in Sardinia. This uncertainty concerning the age poses limitations to reconstructing the Palaeozoic stratigraphy, defining the Alpine and pre-Alpine histories and correlations with other domains of the Variscan chain. We present the UPb age of detrital zircon and the 40Ar39Ar age of metamorphic muscovite for the Calamita Schist and Ortano Porphyroid, two metamorphic units of undetermined Palaeozoic age cropping out in the eastern Elba Island. The radioisotopic data allows us to: (i) define the Early Carboniferous and Middle Ordovician ages for the Calamita Schist and Ortano Porphyroid, respectively, as well as their derivation (flysch deposit and magmatic rocks); (ii) pose some constraints concerning their alpine tectonic and metamorphic histories. These new data generate a more precise reconstruction of the Palaeozoic sequence in the northern Apennines, and they document that the Palaeozoic basement involved in the alpine deformation underwent internal stacking with an inversion of the original sequence. Copyright © 2010 John Wiley & Sons, Ltd.
    Beschreibung: Published
    Beschreibung: 288-310
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): northern Apennines ; Palaeozoic basement ; U-Pb zircon ; 40Ar-39Ar muscovite ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    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 (20s to 50s) coda waveforms for this earthquake. 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 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: TRANSFER (STREP-037058), CGL2008-01830, Consolider TopoIberia CSD2006-00041.
    Beschreibung: In press
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Adjoint method ; Coda waves ; Surface-wave reflections ; Radiation pattern ; Lateral heterogeneity ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.06. Methods::05.06.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 30
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: A study of the seismic coda of seven small earthquakes recorded on the Teide Volcano-Canary Islands (Spain) was carried out using a temporary, small- aperture, 12-station, seismic array. The purpose was to measure backazimuth, ap- parent velocity and the type of waves that compose the coda in the frequency range 4 to 6 Hz. We used the zero-lag cross-correlation (ZLC) method to obtain the com- ponents of the wave vector and three-component analysis techniques based on the covariance matrix of the signal in the time domain to investigate the polarization properties of the signals. The results show that a great part of the coda signals in the analyzed frequency range are almost uncorrelated, while a low number of isolated correlated arrivals show an apparent slowness between 2 × 10-3 and 2.5 × 10-4 sec/m and an almost random distribution of backazimuths. The correlated arrivals have been interpreted as generated by strong scatterers, probably related to the presence, in the study area, of surface topography irregularities (the volcanic cone and the caldera rim). The wave type varies waves with some Rayleigh components.
    Beschreibung: Published
    Beschreibung: 1637-1647
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic scattering ; Arrays ; 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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  • 31
    Publikationsdatum: 2017-04-04
    Beschreibung: Coda-Q estimates for the Granada Basin (Southern Spain) are obtained by analyzing earthquakes occurring within or close to the borders of this area. The data set is composed of 54 earthquakes with local magnitudes ranging between 2.2 and 4.0 and with epicentral distances to the nearest station smaller than 10 km. A single-scattering process is assumed. Coda-Q values obtained show a clear dependence on frequency according to the relationship Q = Qof", where n ranges from 0.81 to 0.89. After removing the main site effects and discussing the possible multiple-scattering influence, the lapse-time dependence is interpreted as due to attenuation variations with depth. This result agrees with the variation of coda Q obtained by using different sets of events with increasing hypocentral depth ranges.
    Beschreibung: Published
    Beschreibung: 1232-1244
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic attenuation ; Coda-Q ; 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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  • 32
    Publikationsdatum: 2017-04-04
    Beschreibung: In this paper, we adopt three ground-motion simulation techniques (EXSIM, Motazedian and Atkinson, 2005, DSM, Pacor et al., 2005 and HIC, Gallovič and Brokešová, 2007), with the aim of investigating the different performances in near-fault strong-motion modeling and prediction from past and future events. The test case is the 1980, M 6.9, Irpinia earthquake, the strongest event recorded in Italy. First, we simulate the recorded strong-motion data and validate the model parameters by computing spectral acceleration and peak amplitudes residual distributions. The validated model is then used to investigate the influence of site effects and to compute synthetic ground motions around the fault. Afterward, we simulate the expected ground motions from scenario events on the Irpinia fault, varying the hypocenters, the rupture velocities and the slip distributions. We compare the median ground motions and related standard deviations from all scenario events with empirical ground motion prediction equations (GMPEs). The synthetic median values are included in the median ± one standard deviation of the considered GMPEs. Synthetic peak ground accelerations show median values smaller and with a faster decay with distance than the empirical ones. The synthetics total standard deviation is of the same order or smaller than the empirical one and it shows considerable differences from one simulation technique to another. We decomposed the total standard deviation into its between-scenario and within-scenario components. The larger contribution to the total sigma comes from the latter while the former is found to be smaller and in good agreement with empirical inter-event variability.
    Beschreibung: In press
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Irpinia 1980 earthquake ; ground-motion simulation ; ground-motion variability ; scenario events ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 33
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: Broadband waveform inversion of ground velocities in the 0.02 0.10 Hz frequency band is successfully applied to 181 earthquakes with ML ≥ 3 of the April, 2009, L'Aquila, Italy, earthquake sequence. This was made possible by the development of a new regional crustal velocity model constrained by deep crustal profiles, surfacewave dispersion and teleseismic Pwave receiver functions and tested through waveform fit. Although all earthquakes exhibit normal faulting, with the fault plane dipping southwest at about 55º for the majority of events, a subset of events had much shallower dips. The issue of confidence in the derived parameters was investigated by applying the same inversion procedure by two groups who subjectively selected different traces for inversion. The unexpected difficulty in modeling the regional broadband waveforms of the mainshock as a point source was investigated through an extensive finitefault modeling of broadband velocity and accelerometer data, which placed the location of major moment release updip and about 47 seconds after the initial firstarrival hypocentral parameters.
    Beschreibung: Published
    Beschreibung: 975-993
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): L'Aquila sequence ; focal mechanisms ; 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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  • 34
    Publikationsdatum: 2020-02-24
    Beschreibung: The model developed by Aki and Chouet for the coda wave generation and propagation has been used to calculate the quality factor Q for the zone of the Aeolian Islands, southern Italy, in the frequency range of 1 to 12 Hz, and the scaling properties of the seismic spectrum in the magnitude range of 0.4 to 4.7. The Q found for the Aeolian area has a frequency dependence of the form Q = qf v. The absolute values of Q seem to be dependent on the station and location of the seismic events, confirming the strong lateral heterogeneities in the geological structure beneath the Aeolian Arc. A temporal variation has been noted in the Q calculated at Vulcano station (VPL) in a period of 3 weeks soon after the occurrence of a main shock of M, -- 5.5 located near the station. The scaling behavior of this sequence is similar to that obtained in two areas of California and one portion of Japan, with a corner frequency that remains constant with an increasing seismic moment between magnitudes 1 and 4. It differs substantially from the scaling properties of the Hawaian earthquakes that show a linear pattern, without an increase of the stress drop with magnitude. The fact that Vulcano is an active volcano seems not to influence the scaling properties of the seismic sequence localized very near it. It probably indicates that the aftershocks used for calculating the scaling law are generated out of the volcanic complex Lipari-Vulcano, in a zone with a good capability of accu- mulating the stress.
    Beschreibung: Published
    Beschreibung: 97-108
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Coda-Q ; Seismic Source Scaling ; 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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  • 35
    facet.materialart.
    Unbekannt
    Istituto Nazionale di Geofisica e Vulcanologia
    Publikationsdatum: 2017-04-04
    Beschreibung: The Campi Flegrei caldera is a complex structure with a high population density, located west of the city of Naples. In addition of being an active volcano it is characterized by a high seismic hazard due to both Appennines regional earthquakes and to local earthquakes occurring during the bradyseismic crises. These unrest phenomena are characterized by slow ground vertical movements, particularly active in the central part of the caldera, and by a high number of low-magnitude earthquakes. In this context, the determination of the site transfer functions of the area has a strong relevance for the Civil Defense aimed to determine the hazard of the area. We have calculated the site transfer function with different techniques (H/V and Generalized Inversion technique) and have collected data on the local geology with the aim of correlating the site transfer functions with lithology and topography. This analysis has been performed on three areas: the Astroni crater, the Camaldoli hill and the Agnano plain. A future development will be to extend this analysis to the whole Campi Flegrei area.
    Beschreibung: Published
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Site effects ; Campi Flegrei ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: The seismic activity associated with the catastrophic southern Italy earth- quake was monitored by 11 seismic stations operating before this event, within an epicentral distance of 200 km, and by 32 additional short-period seismom- eters installed soon after the main shock. The hypocenter of this event was located at 40°46'N and 15°18'E, at 16 km depth. The fault-plane solution reveals normal faulting, with tensile axis dipping 18 ° and oriented orthogonal to the axis of the Apennines chain. This mechanism is in good agreement with the stress pattern inferred from some previous earthquakes and the local seismotectonics. The hypocenter locations of more than 600 aftershocks, with local magnitudes greater than 2.4, show a pronounced alignment extending for about 70 km, oriented north 120 ° and scattered laterally less than 15 km. These events are mostly concentrated between 8 and 16 km depth. A cluster of aftershocks occurred close to the hypocenter of the main shock covering a region elongated 25 km which corresponds also to the highly damaged area. No significant spreading of the aftershock area with time is observed, but one of the events with higher magnitude (M, = 4.8, 14 February 1981) is displaced 20 km NW from the tip of the aftershock region. The time evolution of the number of aftershocks fits well Omorrs hyperbolic law with a decay coeffcient of 1.07 __. 0.06. The possibility of a future delayed multiple sequence of large events, as already observed in the past along the central and southern Apennines, is discussed. In particular, a relatively high seismic potential seems to exist along the northern boundary of the 1980 rupture segment.
    Beschreibung: Published
    Beschreibung: 187-200
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Irpinia Earthquake ; Aftershock sequences ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 37
    Publikationsdatum: 2017-04-04
    Beschreibung: Intrinsic and scattering attenuation parameters, Q~ and Qs, have been measured in three different tectonic areas for local and shallow earthquakes located close to the receiver. The approach developed by Wennerberg (1993), which takes into account the numerical correction of the coda-Q parameter for the multiple scat- tering formulation of Zeng, was used to infer from the estimates of coda Q and direct S-wave Q the intrinsic (Qi) and scattering (Qs) Q values. Results for 1 to 12 Hz range show that Q~ is comparable to Qs for the Etna volcano and for the Campi Flegrei area, while Qi for the tectonically active area of Granada is lower than Qs. Coda Q is close to intrinsic Q, suggesting that, at least in the crust, coda Q is a good estimate of the intrinsic Q. Volcanic areas show a reasonable higher degree of heterogeneity, if compared with the nonvolcanic area of Granada.
    Beschreibung: Published
    Beschreibung: 1373-1380
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic scattering ; Seismic attenuation ; 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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  • 38
    Publikationsdatum: 2017-04-04
    Beschreibung: In this study the attenuation mechanism of seismic wave energy in north central Italy is estimated using low-magnitude earthquake local data recorded at six stations managed by INGV. Most of the analysed events are located along the Alpine chain in the zone of Iseo and Garda lakes, while a minor part in the Po valley. The zone investigated is characterized by the occurrence of significantly intense earthquakes (magnitude up to 6.6) the most recent occurred in 2004 close to the city of Sal`o on the coast of the Garda lake (Mw = 5.0). Due to the high population density and presence of industrial activity the investigated area is characterized by a high seismic risk. First, the ordinary Multiple Lapse Time Window Analysis (MLTWA) method is applied in the assumption of uniformvelocity and scattering and the couple of B0, the seismic albedo and Le−1, the extinction length inverse (corresponding to the total attenuation coefficient) is calculated in the frequency bands of 1.5, 3, 6 and 12 Hz. To retrieve more realistic estimates, the obtained values of B0 and Le−1 are corrected taking into account the effects of a depth-dependent earth model, consisting of an earth structure characterized by a transparent upper mantle and a heterogeneous crust. We find that the corrected intrinsic and scattering attenuation parameters (which are proportional to the inverse of the intrinsic/scattering quality factors, QI−1 and Qs−1) are strongly frequency dependent, with a prevalence of scattering attenuation over the intrinsic dissipation. The corrected and uncorrected values of total Q are in agreement with the total Q values obtained with different approaches for the same area.
    Beschreibung: Published
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismic Attenuation ; Coda Waves ; Wave Scattering and Diffraction ; 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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  • 39
    Publikationsdatum: 2017-04-04
    Beschreibung: We reply to a comment by Messina et al., who strongly criticized our paper on the San Pio Fault, by showing that in areas of complex geology such as the central Apennines, where the current tectonic setting results from the superposition of different tectonic regimes, the equation: “most visible active fault = major seismogenic fault” can be misleading.
    Beschreibung: Published
    Beschreibung: 421-423
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Seismotectonics ; morphotectonics ; active fault ; San Pio basin ; 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::04.04.09. Structural geology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 40
    Publikationsdatum: 2017-04-04
    Beschreibung: A properly organized seismic network is a valuable tool for monitoring seismic zones and assessing seismic hazards. In this paper we propose a new method (seismic network evaluation through simulation, SNES) to evaluate the performance of hypocenter location of a seismic network. The SNES method gives, as a function of magnitude, hypocentral depth, and confidence level, the spatial distribution of the number of active stations in the location procedure and their relative azimuthal gaps, along with confidence intervals in hypocentral parameters. The application of the SNES method also permits evaluation of the magnitude of completeness (MC), the background noise levels at the stations, and assessment of the appropriateness of the velocity model used in location routine. Italy sits on a tectonically active plate boundary at the convergence of the Eurasian and African lithospheric plates and has a high level of seismicity. In this paper, we apply the SNES method to the Italian National Seismic Network (Rete Sismica Nazionale Centralizzata dell’Istituto Nazionale di Geofisica e Vulcanologia, RSNC– INGV) which has monitored Italian seismicity since the early 1980s, following the destructive 1980 Irpinia earthquake. In recent years, the RSNC–INGV has grown significantly. In fact, in February 2010, it received signals from 305 seismic stations, 258 with wideband three-component sensors. We constructed SNES maps for magnitudes of 1.5, 2, 2.5, and 3, fixing the hypocentral depth at 10 km and the confidence level at 95%. Through the application of the SNES method, we show that the RSNC–INGV provides the best monitoring coverage in the Apennine Mountains with errors that for M 2, are less than 2 and 4 km for epicenter and hypocentral depth, respectively. At M 2.5 this seismic network is capable of constraining earthquake hypocenters to depths of about 150 km for most of the Italian Peninsula. This seismic network provides a threshold of completeness down to M 2 for almost the entire Italian territory.
    Beschreibung: Published
    Beschreibung: 1213-1232
    Beschreibung: 2.5. Laboratorio per lo sviluppo di sistemi di rilevamento sottomarini
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Italian National Seismic Network ; Magnitude of Completeness ; Location Performance ; Seismic Noise ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 41
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: Calculating seismic hazard usually requires input that includes seismicity associated with known faults, historical earthquake catalogs, geodesy, and models of ground shaking. This paper will address the input generally derived from geologic studies that augment the short historical catalog to predict ground shaking at time scales of tens, hundreds, or thousands of years (e.g., SSHAC 1997). A seismogenic source model, terminology we adopt here for a fault source model, includes explicit three-dimensional faults deemed capable of generating ground motions of engineering significance within a specified time frame of interest. In tectonically active regions of the world, such as near plate boundaries, multiple seismic cycles span a few hundred to a few thousand years. In contrast, in less active regions hundreds of kilometers from the nearest plate boundary, seismic cycles generally are thousands to tens of thousands of years long. Therefore, one should include sources having both longer recurrence intervals and possibly older times of most recent rupture in less active regions of the world rather than restricting the model to include only Holocene faults (i.e., those with evidence of large-magnitude earthquakes in the past 11,500 years) as is the practice in tectonically active regions with high deformation rates. During the past 15 years, our institutions independently developed databases to characterize seismogenic sources based on geologic data at a national scale. Our goal here is to compare the content of these two publicly available seismogenic source models compiled for the primary purpose of supporting seismic hazard calculations by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the U.S. Geological Survey (USGS); hereinafter we refer to the two seismogenic source models as INGV and USGS, respectively. This comparison is timely because new initiatives are emerging to characterize seismogenic sources at the continental scale (e.g., SHARE in the Euro- Mediterranean, http://www.share-eu.org/; EMME in the Middle East, http://www.emmegem. org/) and global scale (e.g., GEM, http://www.globalquakemodel.org/; Anonymous 2008). To some extent, each of these efforts is still trying to resolve the level of optimal detail required for this type of compilation. The comparison we provide defines a common standard for consideration by the international community for future regional and global seismogenic source models by identifying the necessary parameters that capture the essence of geological fault data in order to characterize seismogenic sources. In addition, we inform potential users of differences in our usage of common geological/seismological terms to avoid inappropriate use of the data in our models and provide guidance to convert the data from one model to the other (for detailed instructions, see the electronic supplement to this article). Applying our recommendations will permit probabilistic seismic hazard assessment codes to run seamlessly using either seismogenic source input. The USGS and INGV database schema compare well at a first-level inspection. Both databases contain a set of fields representing generalized fault three-dimensional geometry and additional fields that capture the essence of past earthquake occurrences. Nevertheless, there are important differences. When we further analyze supposedly comparable fields, many are defined differently. These differences would cause anomalous results in hazard prediction if one assumes the values are similarly defined. The data, however, can be made fully compatible using simple transformations.
    Beschreibung: USGS Senior Scientist In Residence
    Beschreibung: Published
    Beschreibung: 519-525
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Active fault ; fault source ; database ; seismic hazard ; Italy ; USA ; 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::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    Publikationsdatum: 2020-02-24
    Beschreibung: Mount Etna produces frequent eruptions from its summit craters and from fissures on its flanks. The flank fissures trend approximately radially to the summit, and are mainly concentrated in three rift zones that are located on the NE, S and W flanks. Many flank eruptions result from lateral magma transfer from the central conduit into fractures intersecting the flanks, although some eruptions are fed through newly formed conduits that are not directly linked to the central conduit. We analyzed the structural features of eruptions from 1900 to the present, one of the most active periods in the documented eruptive history of Etna, which comprised 35 summit and 33 flank events. Except for a small eruption on the W flank in 1974, all of the flank eruptions in this interval occurred on or near the NE and S rifts. Eruptions in the NE sector were generally shorter, but their fissure systems developed more rapidly and were longer than those in the S sector. In contrast, summit eruptions had longer mean durations, but generally lower effusion rates (excluding paroxysmal events characterized by very high effusion rates that lasted only a few hours). This database was examined considering the main parameters (frequency and strike) of the eruptive fissures that were active over the last ~2 ka. The distribution in time and space of summit and flank eruptions appears to be closely linked to the dynamics of the unstable E to S flank sector of Etna, which is undergoing periodic displacements induced by subvolcanic magma accumulation and gravitational pull. In this framework, magma accumulation below Etna exerts pressure against the unbuttressed E and S flanks, which have moved away from the rest of the volcano. This has caused an extension to the detachment zones, and has facilitated magma transfer from the central conduit into the flanks.
    Beschreibung: This work was sponsored by the Italian National Civil Defence Department and INGV (Istituto Nazionale di Geofisica e Vulcanologia), project V3-LAVA (RU01–Team 01C).
    Beschreibung: Published
    Beschreibung: 464-479
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: 5.3. TTC - Banche dati vulcanologiche
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): dike ; magmas ; tectonics ; structural geology ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    Publikationsdatum: 2017-04-04
    Beschreibung: In the northern Apennines, the Palaeozoic basement involved in the Late Oligocene–Middle Miocene nappe stack contains metamorphic units for which hypothetical ages have been assigned on the basis of lithological correlations with the Palaeozoic formations of the Variscan chain in Sardinia. This uncertainty concerning the age poses limitations to reconstructing the Palaeozoic stratigraphy, defining the Alpine and pre-Alpine histories and correlations with other domains of the Variscan chain. We present the U-Pb age of detrital zircon and the 40Ar-39Ar age of metamorphic muscovite for the Calamita Schist and Ortano Porphyroid, two metamorphic units of undetermined Palaeozoic age cropping out in the eastern Elba Island. The radioisotopic data allows us to: (i) define the Early Carboniferous and Middle Ordovician ages for the Calamita Schist and Ortano Porphyroid, respectively, as well as their derivation (flysch deposit and magmatic rocks); (ii) pose some constraints concerning their alpine tectonic and metamorphic histories. These new data generate a more precise reconstruction of the Palaeozoic sequence in the northern Apennines, and they document that the Palaeozoic basement involved in the alpine deformation underwent internal stacking with an inversion of the original sequence.
    Beschreibung: In press
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): northern Apennines ; Palaeozoic basement ; U-Pb zircon ; 40Ar-39Ar muscovite ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Publikationsdatum: 2017-04-04
    Beschreibung: We present the first application of a time reverse location method in a volcanic setting, for a family of long-period (LP) events recorded on Mt Etna. Results are compared with locations determined using a full moment tensor grid search inversion and cross-correlation method. From 2008 June 18 to July 3, 50 broad-band seismic stations were deployed on Mt Etna, Italy, in close proximity to the summit. Two families of LP events were detected with dominant spectral peaks around 0.9 Hz. The large number of stations close to the summit allowed us to locate all events in both families using a time reversal location method. The method involves taking the seismic signal, reversing it in time, and using it as a seismic source in a numerical seismic wave simulator where the reversed signals propagate through the numerical model, interfere constructively and destructively, and focus on the original source location. The source location is the computational cell with the largest displacement magnitude at the time of maximum energy current density inside the grid. Before we located the two LP families we first applied the method to two synthetic data sets and found a good fit between the time reverse location and true synthetic location for a known velocity model. The time reverse location results of the two families show a shallow seismic region close to the summit in agreement with the locations using a moment tensor full waveform inversion method and a cross-correlation location method.
    Beschreibung: In press
    Beschreibung: (11)
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Volcano seismology ; Computational seismology ; Wave propagation ; 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
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Publikationsdatum: 2017-04-03
    Beschreibung: After an earthquake, rapid, real-time assessment of hazards such as ground shaking and tsunami potential is important for early warning and emergency response. Tsunami potential depends on sea floor displacement, which is related to the length, L, width, W, mean slip, D, and depth, z, of earthquake rupture. Currently, the primary discriminant for tsunami potential is the centroid-moment tensor magnitude, MwCMT, representing the seismic potency LWD, and estimated through an indirect, inversion procedure. The obtained MwCMT and the implied LWD value vary with the depth of faulting, assumed earth model and other factors, and is only available 30 min or more after an earthquake. The use of more direct procedures for hazard assessment, when available, could avoid these problems and aid in effective early warning. Here we present a direct procedure for rapid assessment of earthquake tsunami potential using two, simple measures on P-wave seismograms – the dominant period on the velocity records, Td, and the likelihood that the high-frequency, apparent rupture-duration, T0, exceeds 50-55 sec. T0 can be related to the critical parameters L and z, while Td may be related to W, D or z. For a set of recent, large earthquakes, we show that the period-duration product TdT0 gives more information on tsunami impact and size than MwCMT and other currently used discriminants. All discriminants have difficulty in assessing the tsunami potential for oceanic strike-slip and back-arc or upper-plate, intraplate earthquake types. Our analysis and results suggest that tsunami potential is not directly related to the potency LWD from the “seismic” faulting model, as is assumed with the use of the MwCMT discriminant. Instead, knowledge of rupture length, L, and depth, z, alone can constrain well the tsunami potential of an earthquake, with explicit determination of fault width, W, and slip, D, being of secondary importance. With available real-time seismogram data, rapid calculation of the direct, period- duration discriminant can be completed within 6-10 min after an earthquake occurs and thus can aid in effective and reliable tsunami early warning.
    Beschreibung: In press
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Earthquake dynamics ; Earthquake source observations ; Seismic monitoring ; Body waves ; Early warning ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    facet.materialart.
    Unbekannt
    Istituto Nazionale di Geofisica e Vulcanologia
    Publikationsdatum: 2017-04-04
    Beschreibung: In the framework of ground-motion amplification analysis for southern Italy, the main target of this study is to provide new constraints on onedimensional, shallow-velocity profiles for a site in the San Fele area near the city of Potenza (southern Italy) where a permanent Irpinia Seismic Network (ISNet) seismic station is installed. Ambient noise vibrations were recorded during a seismic survey in San Fele, and the data acquired were used to define the shallow shear-wave velocity profiles and thicknesses of the shallow soil layers, through analysis of the dispersion characteristics of the surface waves. Single station and array techniques were used to obtain robust results, which show relatively flat curves of the H/V spectral ratios and variations in shearwave velocities confined to the first 50 m in depth. On the basis of these results for the San Fele site, the present study aims to delineate a standard procedure that can be systematically applied to all of the other ISNet stations to improve site characterization. This will allow more accurate evaluation of peak ground-motion quantities (e.g. peak ground acceleration, peak ground velocity) at rock sites for use in shakemap analysis.
    Beschreibung: AMRA S.c. a r.l.
    Beschreibung: Published
    Beschreibung: 59-68
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Site effects ; seismic noise ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 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 ; 05. General::05.01. Computational geophysics::05.01.01. Data processing
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 47
    Publikationsdatum: 2017-04-04
    Beschreibung: We present analyses of the noise wavefield in the vicinity of VIRGO, the Italy-France gravitational wave observatory located close to Pisa, Italy, with special reference to the vibrations induced by a nearby wind park. The spectral contribution of the wind turbines is investigated using (i) on-site measurements, (ii) correlation of spectral amplitudes with wind speed, (iii) directional properties determined via multichannel measurements, and (iv) attenuation of signal amplitude with distance. Among the different spectral peaks thus discriminated, the one at frequency 1.7 Hz has associated the greatest power, and under particular conditions it can be observed at distances as large as 11 km from the wind park. The spatial decay of amplitudes exhibits a complicate pattern, that we interpret in terms of the combination of direct surface waves and body waves refracted at a deep (_ 800 m) interface between the plio-pleistocenic marine, fluvial and lacustrine sediments and the Miocene carbonate basement. We develop a model for wave attenuation which allows determining the amplitude of the radiation from individual turbines, which is estimated on the order of 300-400 μms−119 /pHz for wind speeds over the 8-14 m/s range. On the base of this model, we then develop a predictive relationship for assessing the possible impact of future, project wind farms.
    Beschreibung: In press
    Beschreibung: (37)
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Seismic Noise ; site effects ; Wave propagation ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Publikationsdatum: 2021-11-09
    Beschreibung: Il 24 maggio 2011, alle 12.40 UTC, la Rete Sismica Nazionale (RSN) dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) ha registrato un evento sismico di magnitudo (ML) 3.1 nel distretto sismico1 [Selvaggi et al., 1996] del Montefeltro (in provincia di Forlì-Cesena). Nelle successive due settimane sono stati localizzati dalla Sala di Sorveglianza Sismica della sede romana dell’INGV oltre 600 eventi di cui 13 di ML ≥ 3.0. Otto di questi eventi più energetici sono accaduti entro le prime 16 ore dalla prima scossa. L’evento di maggiore energia si è verificato la notte tra il 24 e il 25 maggio (ore 22.03 UTC del 24 maggio) con una magnitudo pari a ML 3.7 (Tabella 1). Considerando la peculiare evoluzione della sequenza nelle prime 24 ore dal primo evento, la prossimità dell'area epicentrale all’Alta Val Tiberina (AVT nel seguito) dove è attualmente in corso un esperimento sismico passivo [Progetto NOVAT2; Cattaneo et al., 2011; D’Alema et al., 2011] e l’apprensione che stava diffondendosi tra la popolazione, è stato ritenuto opportuno attivare le procedure di risposta ad una emergenza sismica e predisporre un intervento volto a migliorare la copertura strumentale dell'area. Il 25 maggio, in accordo con i colleghi INGV della Sezione di Pisa, dell’Osservatorio di Arezzo [Braun, 2006], della sede di Ancona e della Fondazione Prato Ricerche3, si è proceduto con l'istallazione di una rete sismica temporanea ad integrazione delle stazioni permanenti già presenti in zona. Nella giornata del 27 maggio, due delle stazioni temporanee sono state predisposte per la trasmissione in tempo reale alla Sala di Sorveglianza Sismica di Roma dei dati acquisiti, per migliorare la precisione delle localizzazioni prodotte. Nel contempo, sono stati curati dei comunicati informativi divulgati attraverso il sito web4 dell’Ente, parzialmente inclusi in questo lavoro, per dare una risposta alla popolazione interessata dalla sequenza e fortemente preoccupata dall’intensificarsi della sismicità. Il presente lavoro, la cui redazione è stata completata mentre la sequenza è ancora in corso, vuole essenzialmente descrivere le procedure che vengono attivate all’INGV in risposta ad una emergenza sismica e fornire uno strumento tecnico di supporto alla successiva elaborazione della base dati raccolta nel corso dell'esperimento. Viene quindi presentata una breve introduzione sulle conoscenze sismologiche dell’area interessata dalla sequenza, vengono descritti i comunicati emessi dall’INGV per informare i cittadini e viene descritto l’intervento della rete sismica temporanea, ovvero la tempistica dell'istallazione, la strumentazione utilizzata, e i siti occupati.
    Beschreibung: Published
    Beschreibung: 1-17
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): Seismic Monitoring ; Emergency ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 49
    Publikationsdatum: 2020-12-22
    Beschreibung: On 6 April 2009, a magnitude Mw = 6.1 earthquake struck the Abruzzi region in central Italy. Despite its moderate size, the earthquake caused more than 300 fatalities and partially destroyed the city of L’Aquila and many surrounding villages. In this study we present a retrospective analysis of the rapid source parameters determination procedure developed at INGV (Scognamiglio et al. 2009) as applied to the L’Aquila seismic sequence. Our approach consists of two stages: the near real-time determination of the seismic moment tensor, which is already routinely performed for all M≥ 3.5 earthquakes; and the rapid imaging of the rupture history on a finite fault for earthquakes with M≥ 6.0.
    Beschreibung: Published
    Beschreibung: 892-906
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): moment tensor ; velocity models ; strong-motion ; gps ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 50
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: We describe the automatic (AUTO) and the reviewed (REV) seismic time-domain moment tensor (TDMT) procedures implemented recently at the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Italy. The solutions are obtained from the high-quality data of the recently installed Italian broadband network and of the Mediterranean seismographic network (MedNet). AUTO- and REV-TDMT adopt the long-period full waveform inversion code developed by Dreger and Helmberger (1993). AUTO-TDMT is triggered by local and regional events with magnitude ML 〉=3.5 detected by the INGV seismic center. Moment tensor solutions are available within about 10 min after earthquake location, and they are automatically published on the World Wide Web for solution qualities exceeding a predefined threshold. REV-TDMT solutions are posted on the World Wide Web and included in the INGV-TDMT catalog after manual revision. The catalog we describe has great potential to improve our understanding of the regional seismicity and of the ongoing tectonics because the TDMT solutions are the only moment tensors and moment magnitudes released for Italy for many of the events with ML 〈=4.2.
    Beschreibung: This work has been funded by the 2005–2007 DPC-S4 and 2008–2010 DPC-S3 Italian Civil Protection contracts.
    Beschreibung: Published
    Beschreibung: 2223-2242
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): moment tensor ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    Publikationsdatum: 2017-04-04
    Beschreibung: The 31 October and 1 November 2002, Molise earthquakes (both MW 5.7) were caused by right-lateral slip between 12 and 20 km depth. These earthquakes are the result of large-scale reactivation of pre-existing, left-lateral, regionally extended E-W structures of Mesozoic age. Although recorded ground motions were generally smaller than expected for typical Italian earthquakes, a recent paper attributes a stress drop as high as 180 bars to the Molise earthquakes. We remark that a high stress drop is in contrast both with the relatively long source duration inferred in previous investigations and with geodetic evidence for a significantly smaller fault slip compared with other Apennines earthquakes having similarly large rupture area (e.g. 1997 Umbria-Marche earthquakes). We analyzed both ground acceleration spectra of the mainshocks and single-station spectral ratios of broad-band seismograms in an extended magnitude range (2.7 ≤ MW ≤ 5.7). Our results show that neither the spectral amplitudes of recorded ground motions nor the spectral ratios can be fit by a high stress drop source. Instead we find that the observations are consistent with a low stress drop, our best estimates ranging between 6 and 25 bars, in agreement with the relatively long source duration and small coseismic slip. We interpret the low stress of the 2002 Molise earthquakes in terms of lower energy release mechanisms due to the reutilization of faults reactivated opposite to their original sense of slip.
    Beschreibung: Published
    Beschreibung: 307-324
    Beschreibung: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Beschreibung: JCR Journal
    Beschreibung: partially_open
    Schlagwort(e): stress drop ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 52
    Publikationsdatum: 2017-04-04
    Beschreibung: The introduction of the linear slip–weakening friction law permits the solution of the elasto–dynamic equation for a rupture which develops on a fault, by removing the singularity in the components of stress tensor, thereby ensuring a finite energy flux at the crack tip. With this governing model, largely used by seismologists, it is possible to simulate a single earthquake event but, in absence of remote tectonic loading, it requires the introduction of an artificial procedure to initiate the rupture, i.e, to reach the failure stress point. In this paper, by studying the dynamic rupture propagation and the solutions on the fault and on the free surface, we systematically compare three conceptually and algorithmically different nucleation strategies widely adopted in the literature: the imposition of an initially constant rupture speed, the introduction of a shear stress asperity, and the perturbation to the initial particle velocity field. Our results show that, contrarily to supershear ruptures which tend to “forget” their origins, subshear ruptures are quite sensitive to the adopted nucleation procedure, which can bias the runaway rupture. We confirm that that the most gradual transition from imposed nucleation and spontaneous propagation is obtained by initially forcing the rupture to expand at a properly chosen, constant speed (0.75 times the Rayleigh speed). We also numerically demonstrate that a valid alternative to this strategy is an appropriately smoothed, elliptical shear stress asperity. Moreover, we evaluate the optimal size of the nucleation patch where the procedure is applied; our simulations indicate that its size has to equal the critical distance of Day (1982) in case of supershear ruptures and to exceed it in case of subshear ruptures.
    Beschreibung: In press
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Nucleation strategies ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 53
    Publikationsdatum: 2017-04-04
    Beschreibung: This study investigates the engineering applicability of two conceptually different finite-fault simulation techniques. We focus our attention on two important aspects: first to quantify the capability of the methods to reproduce the observed ground-motion parameters (peaks and integral quantities); second to quantify the dependence of the strong-motion parameters on the variability in the large-scale kinematic definition of the source (i.e., position of the nucleation point, value of the rupture velocity, and distribution of the final slip on the fault). We applied an approximated simulation technique, the deterministic-stochastic method and a broadband technique, the hybrid-integral-composite method, to model the 1984 Mw 5.7 Gubbio, central Italy, earthquake, at five accelerometric stations. We first optimize the position of the nucleation point and the value of the rupture velocity for three different final slip distributions on the fault by minimizing an error function in terms of acceleration response spectra in the frequency band from 1 to 9 Hz. We found that the best model is given by a rupture propagating at about 2:65 km=sec from a hypocenter located approximately at the center of the fault. In the second part of the article we calculate more than 2400 scenarios varying the kinematic source parameters. At the five sites we compute the residuals distributions for the various strongmotion parameters and show that their standard deviations depend on the source parameterization adopted by the two techniques. Furthermore, we show that Arias Intensity (AI) and significant duration are characterized by the largest and smallest standard deviation, respectively. Housner Intensity is better modeled and less affected by uncertainties in the source kinematic parameters than AI. The fact that the uncertainties in the kinematic model affects the variability of different ground-motion parameters in different ways has to be taken into account when performing hazard assessment and earthquake engineering studies for future events.
    Beschreibung: Published
    Beschreibung: 647-663
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): ground-motion simulation ; Gubbio 1984 ; ground-motion variability ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    Publikationsdatum: 2017-04-04
    Beschreibung: In April 1998, a swarm of 1800 microearthquakes near the village of Iznajar (southern Spain) was recorded at the Granada basin short-period seismic network. Focal mechanisms from local P-wave polarities are poorly constrained and cannot characterize the seismotectonics of the series. Here we combine polarity information and multiplet relocation to address this issue. We use waveform cross correlation on P and S arrivals to identify events with highly similar seismograms, group our detections into multiplet clusters, and invert the cross-correlation time delays to obtain precise relative locations. Relative locations have errors of several tens to a few hundreds of meters horizontally and vertically, and define strike and dip of active fault patches with an accuracy of 20°–30°. We introduce the multiplet fault plane orientations into focal mechanism inversion, now yielding mostly well-constrained solutions, in addition to resolving the nodal plane symmetry. We observe mainly north-south left-lateral strike-slip faulting and a few north-northwest–south-southeast normal faulting solutions, illustrating the kinematic complexity of the swarm, and pointing to a local deformation style different from the nearby Granada basin.
    Beschreibung: Published
    Beschreibung: 3421-3429
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Fault plane solution ; Precise location ; Seismic swarm ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 55
    Publikationsdatum: 2017-04-04
    Beschreibung: We present a duration-amplitude procedure for rapid determination of a moment magnitude, Mwpd, for large earthquakes using P-wave recordings at teleseismic distances. Mwpd can be obtained within 20 minutes or less after the event origin time as the required data is currently available in near-real time. The procedure determines apparent source durations, T0, from high-frequency, P-wave records, and estimates moments through integration of broadband displacement waveforms over the interval tP to tP+T0, where tP is the P arrival time. We apply the duration-amplitude methodology to 79 recent, large earthquakes (Global Centroid- Moment Tensor magnitude, MwCMT, 6.6 to 9.3) with diverse source types. The results show that a scaling of the moment estimates for interplate thrust and possibly tsunami earthquakes is necessary to best match MwCMT. With this scaling, Mwpd matches MwCMT typically within ±0.2 magnitude units, with a standard deviation of σ=0.11, equaling or outperforming other approaches to rapid magnitude determination. Furthermore, Mwpd does not exhibit saturation; that is, for the largest events, Mwpd does not systematically underestimate MwCMT. The obtained durations and duration-amplitude moments allow rapid estimation of an energy-to-moment parameter Θ* used for identification of tsunami earthquakes. Our results show that Θ* ≤ -5.7 is an appropriate cutoff for this identification, but also show that neither Θ* nor Mw is a good indicator for tsunamigenic events in general. For these events we find that a reliable indicator is simply that the duration T0 is greater than about 50 sec. The explicit use of the source duration for integration of displacement seismograms, the moment scaling, and other characteristics of the duration-amplitude methodology make it an extension of the widely used, Mwp, rapid-magnitude procedure. The need for a moment scaling for interplate thrust and possibly tsunami earthquakes may have important implications for the source physics of these events.
    Beschreibung: DPC-INGV (2007-2009) S3 Project
    Beschreibung: Published
    Beschreibung: 200-214
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): earthquakes, Richter magnitude, seismic moment, seismograms, tsunami,  earthquake­source mechanism ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 56
    Publikationsdatum: 2017-04-04
    Beschreibung: The introduction of the linear slip–weakening friction law permits the solution of the elasto–dynamic equation for a rupture which develops on a fault, by removing the singularity in the components of stress tensor, thereby ensuring a finite energy flux at the crack tip. With this governing model, largely used by seismologists, it is possible to simulate a single earthquake event but, in absence of remote tectonic loading, it requires the introduction of an artificial procedure to initiate the rupture, i.e, to reach the failure stress point. In this paper, by studying the dynamic rupture propagation and the solutions on the fault and on the free surface, we systematically compare three conceptually and algorithmically different nucleation strategies widely adopted in the literature: the imposition of an initially constant rupture speed, the introduction of a shear stress asperity, and the perturbation to the initial particle velocity field. Our results show that, contrarily to supershear ruptures which tend to “forget” their origins, subshear ruptures are quite sensitive to the adopted nucleation procedure, which can bias the runaway rupture. We confirm that that the most gradual transition from imposed nucleation and spontaneous propagation is obtained by initially forcing the rupture to expand at a properly chosen, constant speed (0.75 times the Rayleigh speed). We also numerically demonstrate that a valid alternative to this strategy is an appropriately smoothed, elliptical shear stress asperity. Moreover, we evaluate the optimal size of the nucleation patch where the procedure is applied; our simulations indicate that its size has to equal the critical distance of Day (1982) in case of supershear ruptures and to exceed it in case of subshear ruptures.
    Beschreibung: Published
    Beschreibung: 923–940
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Earthquake nucleation ; Computational seismology ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 57
    Publikationsdatum: 2017-04-04
    Beschreibung: Horizontal-to-vertical spectral ratios using ambient noise (HVNSR) are commonly used in site effects studies. In the practice, many operators assume stability over time of HVNSR and base their analyses on few very short time windows. The availability of a long period of continuous microtremor recording allowed us to analyze three months of data coming from a dense array experiment performed at Cavola, a village in northern Apennines. This condition offers a good opportunity to check the validity of the stability assumption and to investigate variations of the local ambient noise wave-field composition. The Cavola site is characterized by landslide sediments over stiffer materials with a moderate impedance contrast and by a complex morphology. An intense industrial activity in the village contributes to the generation of seismic noise. After identifying this noise source in the time series, we evaluate its effects on HVNSR. The results indicate that the spectral peak of HVNSR varies in amplitude and frequency, posing a warning about stability in time. Analyzing the spectra we identify the anthropic activity as responsible for changes in the composition of the noise wave field. These variations affect HVNSR, including peak frequency and also ground-motion polarization.
    Beschreibung: Published
    Beschreibung: 1263-1275
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): noise measurements ; Rayleigh waves ; polarization ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 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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  • 58
    Publikationsdatum: 2017-04-04
    Beschreibung: IEEE Standard for Local and Metropolitan Area Networks (hereafter IEEE 802.16; online at http://standards.ieee.org/getieee802/802.16.html) is one of the most promising mobile and fixed broadband wireless access technologies for next-generation all-IP networks in the 3.5 GHz band (European spectrum profile). Commonly known as Universal WiMAX (worldwide inter-operability for microwave access), this access technology reaches a high bit rate and covers large areas with a single base station, making it possible to offer connectivity to end users in a cost-effective way. A further useful property of the WiMAX technology is that the transmission can be used both in line-of-sight (LOS) and non-line-of-sight (NLOS) environments, allowing highly feasible communications (WiMAX Forum 2004). Thanks to these features, IEEE 802.16 opens the way to the use of wireless technologies in the environmental monitoring of areas such as seismic and volcanic zones.
    Beschreibung: European Community’s Sixth Framework Programme, Contract no. IST-034622-IP
    Beschreibung: Published
    Beschreibung: 411-419
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): WiMAX ; volcano monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 59
    facet.materialart.
    Unbekannt
    Istituto Nazionale di Geofisica e Vulcanologia
    Publikationsdatum: 2017-04-04
    Beschreibung: L’uso del rumore ambientale nella valutazione della risposta sismica locale sta diventando molto frequente data la sua facile applicabilità e sensibilità alla variazione spaziale della geologia superficiale. Ciò lo rende particolarmente adatto nelle aree urbane, dove la natura delle unità geologiche affioranti è mascherata dagli interventi antropici. Il lavoro descrive i metodi di acquisizione e di trattamento dei dati, utilizzati durante una campagna svoltasi nell'area urbana di Catania.
    Beschreibung: Published
    Beschreibung: 1-30
    Beschreibung: 1.8. Osservazioni di geofisica ambientale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): NOISE ; ACQUISIZIONE ; URBANA ; CATANIA ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 05. General::05.01. Computational geophysics::05.01.01. Data processing
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 60
    Publikationsdatum: 2022-06-14
    Beschreibung: On 6 April 2009, at 01:32 GMT, an Mw 6.3 seismic event hit the central Apennines, severely damaging the town of L’Aquila and dozens of neighboring villages and resulting in approximately 300 casualties (Istituto Nazionale di Geofisica e Vulcanologia, http://www.ingv.it; MedNet, http://mednet.rm.ingv.it/proce- dure/events/QRCMT/090406_013322/qrcmt.html). This earth- quake was the strongest in central Italy since the devastating 1915 Fucino event (Mw 7.0). The INGV national seismic net- work located the hypocenter 5 km southwest of L’Aquila, 8–9 km deep. Based on this information and on the seismotectonic framework of the region, earthquake geologists traveled to the field to identify possible surface faulting (Emergeo Working Group 2009a, 2009b). The most convincing evidence of pri- mary surface rupture is along the Paganica fault, the geometry of which is consistent with seismological, synthetic aperture radar (SAR) and GPS data. Investigation of other known nor- mal faults of the area, i.e., the Mt. Pettino, Mt. San Franco, and Mt. Stabiata normal faults suggested that these structures were not activated during the April 6 shock (Emergeo Working Group 2009a, 2009b). In this report, we first describe the seismotectonic frame- work of the area, and then we present the field information that supports the occurrence of surficial displacement on the Paganica fault.
    Beschreibung: Published
    Beschreibung: 940-950
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Surface coseismic ruptures ; Paganica Fault ; earthquake ; 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::04.06. 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::04.06.06. Surveys, measurements, and monitoring ; 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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  • 61
    Publikationsdatum: 2020-12-22
    Beschreibung: The determination of regional attenuation Q^-1 can depend upon the analysis method employed. The discrepancies between methods are due to differing parameterizations (e.g., geometrical spreading rates), employed datasets (e.g., choice of path lengths and sources), and the methodologies themselves (e.g., measurement in the frequency or time domain). Here we apply five different attenuation methodologies to a Northern California dataset. The methods are: (1) coda normalization (CN), (2) two-station (TS), (3) reverse two-station (RTS), (4) source-pair/receiver-pair (SPRP), and (5) coda-source normalization (CS). The methods are used to measure Q of the regional phase, Lg (QLg), and its power-law dependence on frequency of the form Q0fη with controlled parameterization in the well-studied region of Northern California using a high-quality dataset from the Berkeley Digital Seismic Network. We investigate the difference in power-law Q calculated among the methods by focusing on the San Francisco Bay Area, where knowledge of attenuation is an important part of seismic hazard mitigation. This approximately homogeneous subset of our data lies in a small region along the Franciscan block. All methods return similar power-law parameters, though the range of the joint 95% confidence regions is large (Q0 = 85 ± 40; η = 0.65 ± 0.35). The RTS and TS methods differ the most from the other methods and from each other. This may be due to the removal of the site term in the RTS method, which is shown to be significant in the San Francisco Bay Area. In order to completely understand the range of power-law Q in a region, it is advisable to use several methods to calculate the model. We also test the sensitivity of each method to changes in geometrical spreading, Lg frequency bandwidth, the distance range of data, and the Lg measurement window. For a given method, there are significant differences in the power-law parameters, Q0 and η, due to perturbations in the parameterization when evaluated using a conservative pairwise comparison. The CN method is affected most by changes in the distance range, which is most probably due to its fixed coda measurement window. Since, the CS method is best used to calculate the total path attenuation, it is very sensitive to the geometrical spreading assumption. The TS method is most sensitive to the frequency bandwidth, which may be due to its incomplete extraction of the site term. The RTS method is insensitive to parameterization choice, whereas the SPRP method as implemented here in the time-domain for a single path has great error in the power-law model parameters and η is strongly affected by changes in the method parameterization. When presenting results for a given method it is best to calculate Q0f^η for multiple parameterizations using some a priori distribution.
    Beschreibung: Published
    Beschreibung: 2033–2046
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Q attenuation ; 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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  • 62
    Publikationsdatum: 2017-04-04
    Beschreibung: This study investigates the engineering applicability of two conceptually different finite-fault simulation techniques. We focus our attention on two important aspects: first to quantify the capability of the methods to reproduce the observed ground-motion parameters (peaks and integral quantities); second to quantify the dependence of the strong-motion parameters on the variability in the large-scale kinematic definition of the source (i.e. position of nucleation point, value of the rupture velocity and distribution of the final slip on the fault). We applied an approximated simulation technique, the Deterministic-Stochastic Method DSM, and a broadband technique, the Hybrid-Integral-Composite method HIC, to model the 1984 Mw 5.7 Gubbio, central Italy, earthquake, at 5 accelerometric stations. We first optimize the position of nucleation point and the value of rupture velocity for three different final slip distributions on the fault by minimizing an error function in terms of acceleration response spectra in the frequency band from 1 to 9 Hz. We found that the best model is given by a rupture propagating at about 2.65 km/s from a hypocenter located approximately at the center of the fault. In the second part of the paper we calculate more than 2400 scenarios varying the kinematic source parameters. At the five sites we compute the residuals distributions for the various strong-motion parameters and show that their standard deviations depend on the source-parameterization adopted by the two techniques. Furthermore, we show that, Arias Intensity and significant duration are characterized by the largest and smallest standard deviation, respectively. Housner Intensity results better modeled and less affected by uncertainties in the source kinematic parameters than Arias Intensity. The fact that the uncertainties in the kinematic model affects the variability of different ground-motion parameters in different ways has to be taken into account when performing hazard assessment and earthquake engineering studies for future events.
    Beschreibung: In press
    Beschreibung: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): ground-motion simulation ; Gubbio 1984 ; ground-motion variability ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 63
    Publikationsdatum: 2017-04-04
    Beschreibung: A 1D coda method was proposed by Mayeda et al. (2003) in order to obtain stable seismic source moment-rate spectra using narrowband coda envelope measurements. That study took advantage of the averaging nature of coda waves to derive stable amplitude measurements taking into account all propagation, site, and S-to-coda transfer function effects. Recently, this methodology was applied to microearthquake data sets from three subregions of northern Italy (i.e., western Alps, northern Apennines, and eastern Alps). Because the study regions were small, ranging between local-to-near-regional distances, the simple 1D path assump- tions used in the coda method worked very well. The lateral complexity of this region would suggest, however, that a 2D path correction might provide even better results if the data sets were combined, especially when paths traverse larger distances and com- plicated regions. The structural heterogeneity of northern Italy makes the region ideal to test the extent to which coda variance can be reduced further by using a 2D Q tomography technique. The approach we use has been developed by Phillips et al. (2005) and is an extension of previous amplitude ratio techniques to remove source effects from the inversion. The method requires some assumptions, such as isotropic source radiation, which is generally true for coda waves. Our results are compared against direct S-wave inversions for 1/Q and results from both share very similar attenuation features that coincide with known geologic structures. We compare our results with those derived from direct waves as well as some recent results from northern California obtained by Mayeda et al. (2005) that tested the same tomo- graphic methodology applied in this study to invert for 1/Q. We find that 2D coda path corrections for this region significantly improve upon the 1D corrections, in contrast to California where only a marginal improvement was observed. We attribute this difference to stronger lateral variations in Q for northern Italy relative to California.
    Beschreibung: Published
    Beschreibung: 1936-1946
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Attenuation tomography ; 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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  • 64
    Publikationsdatum: 2017-04-04
    Beschreibung: In this note, we investigate the characteristics of ambient noise cross-correlations for station pairs in northern Italy, considering the secondary microseism bandwidth (0.1-0.6 Hz). The preliminary analysis that we performed exploiting the available continuous recording in the investigated area, agrees with the recent results of Pedersen et al. (2007): the directionality of the noise signal cannot be disregarded when the group velocity is estimated in the range 0.1-0.6 Hz and the selection of the path orientation for tomography must be carefully performed. In particular, while the favourable directions with respect to microseisms generated along the Atlantic coasts of France, Norway and British Islands cover a quite wide azimuthal range (from about 270N to 5N), allowing us to reliably estimate the fundamental mode Rayleigh group velocity for paths in the Alps (about 2.7 km/s), more care must be taken when the microseisms are generated in the Mediterranean Sea. In that case, different locations of the generating areas of microseisms could provide biased estimates of the group velocity due to differences between the true and the apparent velocity of propagation between the stations.
    Beschreibung: Published
    Beschreibung: 1389-1398
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): microseisms ; ambient noise ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 65
    Publikationsdatum: 2017-04-04
    Beschreibung: The April 18, 1906 M8 California earthquake generated a small local tsunami that was recorded in the near-field by the Presidio, San Francisco tide-gage, located near the Golden Gate. We investigate the causative, tsunamigenic seismic source by forward modeling and nonlinear inversion of the Presidio marigram. We use existing seismological and geological observations to fix the fault system geometry and the surface slip on the onland portions of the San Andreas fault (SAF). We perform synthetic inversions to show that the single, near-field marigram constrains the main features of the rupture on the portion of the SAF system offshore of the Golden Gate. Finally we perform nonlinear inversions for the slip distribution and the timing of the rupture of the 1906 earthquake. Our results, in agreement with previous studies, identify a dilatational step-over and show a bi-lateral rupture, possibly originating or propagated through the step-over region. We find that little or no co-seismic slip on normal faults in the step-over region is required to fit the marigram, and we obtain adequate fits when allowing delays in the source initiation times of up to 3 minutes on the various fault segments. We constrain slip to be of about 5-6 meters for the onshore portion of the SAF to the northwest of the Golden Gate, in agreement with 1906 surface observations of fault offset. Our results favour the hypothesis of a vertical dip for a currently aseismic SAF to the southeast of the Golden Gate, under the San Francisco Peninsula.
    Beschreibung: Published
    Beschreibung: 832-845
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: partially_open
    Schlagwort(e): rupture process ; tsunami ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 66
    Publikationsdatum: 2017-04-04
    Beschreibung: The Campi Flegrei (southern Italy) is one of the most active calderas in the world. This caldera is characterized by episodes of slow vertical ground movement, called bradyseism. With several hundred thousand people living within its borders, this area is in a high-risk category should there be an eruption. The seismological monitoring system in the Campi Flegrei is based on nine seismic stations, eight of which are equipped with short-period seismometers (1 Hz), and one with a broadband seismometer (60 sec–50 Hz). While all of the seismic stations are located on land, part of the seismic activity occurs in the undersea area of the Pozzuoli Gulf (Campi Flegrei), where there are no seismic stations. This gap in the data coverage produces a biased and incomplete image of the volcanic area.We carried out an experiment in the Pozzuoli Gulf with the installation of two broadband seismic stations on the seafloor with remote and continuous data acquisition for a duration of 31 days between January and March 2005. Using the data acquired, we have computed the power spectral density (PSD) to characterize the background seismic noise, and to evaluate the true noise variation, we have generated the seismic noise probability density functions from the computed PSD curves. The results of our analysis show that the broadband seismic noise is high when compared with the Peterson noise model (land model), but for periods less than 0.3 sec, the seismic noise on the seafloor is lower than the recordings on land over the same period range. The last bradyseismic crisis (1982–1984) highlights the importance of this frequency range, where most of the spectral content of the recorded earthquakes was observed. Finally, we evaluate the detection threshold of a new seismic station located on the seafloor of the Campi Flegrei caldera considering the characteristics of the local seismicity. This analysis shows that the detection threshold for the sea-floor stations (Mw ∼ 0:2) is less than that for land stations (Mw ∼ 0:8).
    Beschreibung: Published
    Beschreibung: 2962–2974
    Beschreibung: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Campi Flegrei Caldera ; Sea-Floor and On-Land Seismic ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 67
    Publikationsdatum: 2020-11-20
    Beschreibung: Il presente lavoro è costituito dalla raccolta sistematica delle indagini macrosismiche eseguite in occasione dei terremoti più energetici verificatisi in Sicilia orientale dal Gennaio 2002 al Dicembre 2005. Esso rappresenta l’estensione, agli anni più recenti, della compilazione effettuata per il periodo 1999-2001 [Azzaro et al., 2002], e più in generale è inserita nel contesto delle attività di pronto intervento macrosismico effettuate regolarmente in ambito regionale dal 1988. L’esecuzione di rilievi in occasione di eventi sismici significativi è una prassi ormai consolidata nelle attività di monitoraggio dell’INGV, che recentemente ha istituito a tal fine il gruppo di lavoro denominato QUEST (QUick Earthquake Survey Team, DP n° 44 del 25/02/2004). I dati raccolti assolvono ad una duplice funzione: 1) nell’immediatezza di un evento sismico, a definire il quadro degli effetti a supporto degli interventi di Protezione Civile e della Comunità Scientifica; 2) a risolvere lacune e problemi interpretativi dei terremoti del passato attraverso il confronto con gli effetti macrosismici degli eventi attuali. La raccolta sistematica di dati macrosismici anche nel caso di eventi di bassa magnitudo, che interessano estensioni areali limitate come quelle etnee, è comunque importante per l’implementazione di banche dati e cataloghi macrosismici sia a livello locale che nazionale. Nel primo caso è stato aggiornato il catalogo macrosismico dei terremoti etnei [Azzaro et al., 2000], recentemente reso disponibile anche su Internet. Nel secondo caso, la più recente versione del catalogo parametrico dei terremoti italiani [Gruppo di Lavoro CPTI, 2004] utilizzata per la redazione della nuova mappa di pericolosità sismica del territorio nazionale (Ordinanza PCM 3274 del 20/03/2003), incorpora i dati dei terremoti siciliani al di sopra della soglia del danno pubblicati in Azzaro et al. [2002, 2003]. I rilievi macrosismici di seguito riportati sono relativi a tutti i terremoti oltre la soglia del danno verificatisi nel periodo considerato, ovvero a quegli eventi che sono stati avvertiti in modo significativo dalla popolazione (Figura 1). In larga parte si tratta di eventi di area etnea che, soprattutto nel corso del 2002, hanno provocato effetti macrosismici di rilievo. Tra i terremoti regionali riportati, non è incluso il terremoto di Palermo del 2002 per il quale è disponibile uno studio specifico [Azzaro et al., 2003].
    Beschreibung: Published
    Beschreibung: 1-62
    Beschreibung: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Beschreibung: N/A or not JCR
    Beschreibung: open
    Schlagwort(e): NONE ; Sicilia ; terremoti ; macrosismica ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 68
    Publikationsdatum: 2020-12-14
    Beschreibung: We analyze the dispersion characteristics of ambient noise vibrations. For this purpose, two-dimensional (2D) seismic array data were acquired in four different sites in the Colfiorito plain, an alluvial intramountain basin that exhibits strong site effects. Assuming seismic noise being mainly composed of surface waves, we derive one-dimensional (1D) shallow shear-velocity profiles through the inversion of dispersion curves measured by frequency–wavenumber (f-k) methods. The inverted shear-wave velocity profiles are consistent with a priori information for those sites that can be approximated by 1D simple models. In these cases, the use of passive records of seismic vibrations can be a valuable tool for determining the shallow velocity profile if a detailed depiction of velocity structure is not required. The theoretical dispersion curves for Rayleigh and Love waves were compared with the measured dispersion curves for vertical and horizontal components, respectively. This allows us to discuss qualitatively the composition of ambient vibrations (outlining a large proportion of Love waves in the noise wave field) and the effects of higher modes. We also use the single-station method for investigating the origin of the horizontal-to-vertical (H/V) peak in the plain of Colfiorito in terms of ellipticity of the fundamental Rayleigh mode.
    Beschreibung: Published
    Beschreibung: 1915-1933
    Beschreibung: reserved
    Schlagwort(e): surface waves, microtremor, f-k 2D analysis ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 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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  • 69
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-03
    Beschreibung: The aim of this work is to infer the slip distribution and rupture velocity along the rupture zone of the 26 December 2004 Sumatra–Andaman earthquake from available tide gage records of the tsunami. We selected waveforms from 14 stations, distributed along the coast of the Indian Ocean. Then we subdivided the fault plane into 16 subfaults (both along strike and downdip) following the geometry and mechanism proposed by Banerjee et al. (2005) and computed the corresponding Green’s functions by numerical solution of the shallow-water equations through a finitedifference method. The slip distribution and rupture velocity were determined simultaneously by means of a simulated annealing technique. We compared the recorded and synthetic waveforms in the time domain, using a cost function that is a trade-off between the L1 and L2 norms. Preliminary tests on a synthetic dataset, together with a posteriori statistical analysis of the model ensemble enabled us to assess the effectiveness of the method and to quantify the model uncertainty. The main finding is that the best source model features a nonuniform distribution of coseismic slip, with high slip values concentrated into three main patches: the first is located in the southern part of the fault, off the coast of the Aceh Province; the second between 6.5 N and 11 N; and the third at depth, between 11 N and 14 N. Furthermore, we estimated that the rupture propagated at an average speed of 2.0 km/sec.
    Beschreibung: Published
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Sumatra–Andaman Earthquake ; Tsunami ; Waveform Inversion ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 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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  • 70
    Publikationsdatum: 2017-04-04
    Beschreibung: We have analyzed the aftershocks (ML 4.5) following the 1999 Izmit earthquake (Mw 7.4) to infer the frequency-dependent attenuation characteristics of both P and S waves, in the frequency range from 1 to 10 Hz and in the distance range from 10 to 140 km. A linear-predictive model is assumed to describe the spectral amplitudes in terms of attenuation and source contributions. The results show that both P and S waves undergo a strong attenuation along ray paths shorter than 40 km, while the secondary arrivals significantly contribute to the spectral amplitudes over the distance range from 40 to 60 km, as also confirmed by the computation of synthetic seismograms. For longer ray paths, the decrease in attenuation suggests an increase in the propagation efficiency with depth. Finally, the spectral attenuation curves are flattened, or sloped upward at low frequencies in the range from 100 to 140 km, due to the contemporary arrivals of direct waves and postcritical reflections from the Moho. In terms of geometrical spreading and anelastic attenuation, the attenuation in the range from 10 to 40 km is well described by a spreading coefficient n 1 for both P and S waves, and the quality factors can be approximated by QS( f ) 17f 0.80 for 1 f 10 Hz and QP( f ) 56f 0.25 for 2.5 f 10 Hz. For ray paths in the range from 60 to 80 km, the attenuation weakens but the interaction between seismic waves and propagation medium is more complex. The multilapse time window analysis (MLTWA) is applied to quantify the amount of scattering loss and intrinsic absorption for S waves. The seismic albedo B0 decreases from 0.5 at 1 Hz to 0.3 at 10 Hz, while the total quality factor QT increases from about 56 to 408. The multiple lapse time-window analysis (MLTWA) results provide only an average estimate of the attenuation properties in the range from 10 to 80 km. In fact, by neglecting the variation of attenuation with depth, the MLTWA results underestimate attenuation for distances less than 40 km, and do not capture the significant features caused by the integrated energy of the secondary arrivals observed in the range from 40 to 60 km.
    Beschreibung: Published
    Beschreibung: 200-214
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): aftershocks ; 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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  • 71
    Publikationsdatum: 2017-04-04
    Beschreibung: Abstract We present an update of the local magnitude scale previously calibrated for northwestern Turkey by Baumbach et al. (2003). The path coverage in the westernmost part of the analyzed area has been increased, as well as the number of amplitudes for distance greater than 110 km. Furthermore, a set of recordings from accelerometric stations operated by the Kandilli Observatory and Earthquake Research Institute (KOERI) has been merged with the recordings by the Sapanca-Bolu and German Task Force seismological networks. In all, 4047 recordings from 528 earthquakes recorded by 31 seismometers and 23 accelerometers are considered to calibrate the local magnitude scale over a hypocentral distance range from 10 to 190 km. By analyzing the unit covariance matrix and the resolution matrix, we show how the source-to-station geometries of the seismic and strong-motion networks affect the uncertainties of the computed station corrections, attenuation coefficients, and magnitudes. The assumptions made concerning the reference station correction, and the change in the amplification for the Wood–Anderson torsion seismograph from 2800 to 2080 (Uhrhammer and Collins, 1990) introduced an offset of about 0.34 in the magnitudes with respect to Baumbach et al. (2003), with the updated local magnitude scale ranges from 0.50 to 5.91. The distribution of the residuals with distance confirms that the extension of both the magnitude and distance ranges and the improved path coverage have preserved the high quality that characterized the data set analyzed by Baumbach et al. (2003).
    Beschreibung: Published
    Beschreibung: 331-338
    Beschreibung: 3.3. Geodinamica e struttura dell'interno della Terra
    Beschreibung: JCR Journal
    Beschreibung: partially_open
    Schlagwort(e): local magnitude ; 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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  • 72
    Publikationsdatum: 2017-04-03
    Beschreibung: We propose a new source-time function, to be used in kinematic modeling of ground-motion time histories, which is consistent with dynamic propagation of earthquake ruptures and makes feasible the dynamic interpretation of kinematic slip models. This function is derived from a source-time function first proposed by Yoffe (1951), which yields a traction evolution showing a slip-weakening behavior. In order to remove its singularity, we apply a convolution with a triangular function and obtain a regularized source-time function called the regularized Yoffe function. We propose a parameterization of this slip-velocity time function through the final slip, its duration, and the duration of the positive slip acceleration (Tacc). Using this analytical function, we examined the relation between kinematic parameters, such as peak slip velocity and slip duration, and dynamic parameters, such as slip-weakening distance and breakdown-stress drop. The obtained scaling relations are consistent with those proposed by Ohnaka and Yamashita (1989) from laboratory experiments. This shows that the proposed source-time function suitably represents dynamic rupture propagation with finite slip-weakening distances.
    Beschreibung: Published
    Beschreibung: 1211–1223
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: partially_open
    Schlagwort(e): Earthquake dynamics and mechanics ; Earthquake modeling ; Earthquake parameters ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 73
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: Abstract Rapid estimates of source parameters are needed for reasons of civil protection in regions where destructive events often occur. This information can prevent further damage and casualties. A relation between the first seconds of a P- wave onset and the local magnitude ML of the earthquake has been developed for the Italy region following results obtained in Japan and Southern California. The proposed dominant period estimate has been used in the present work and it gives reliable results from which to evaluate the size of the earthquake. The data set we evaluated consists of about 20,000 earthquakes that occurred in Italy and were well recorded by the stations of the MedNet Network. The proposed relationship will be one basis for developing and implementing an earthquake early warning system in Italy capable of delivering a rapid alert only a few seconds after the occurrence of a potentially destructive earthquake in the area. Recent extensive improvements of the Italian National Seismic Network, together with this new technique, will make pos- sible the release of a robust magnitude estimate no later than 10 sec after the occur- rence of the earthquake. However, no data are available for earthquakes with mag- nitudes ML
    Beschreibung: Published
    Beschreibung: 1750-1755
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Magnitude ; early warning ; 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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  • 74
    Publikationsdatum: 2017-04-04
    Beschreibung: The attenuation of shear waves propagating in the crust of northwestern Turkey has been investigated in the frequency range 1–10 Hz. A standard spectral inversion scheme is applied to a data set of 245 aftershocks (ML 4.5) of the 1999 Izmit earthquake. The obtained attenuation-with-distance curves have been described in terms of the t* cumulative attenuation parameter and its dependence on frequency and distance investigated. At 1 Hz, Q 1, evaluated by normalizing t* to the travel time, is generally larger than 0.025 for source-to-station distances smaller than 40 km, indicating the presence of a highly attenuating upper crust in the area. Over longer distances, Q 1 decreases, suggesting a decrease in the attenuation with depth. By contrast, the normalized t* computed for earthquakes recorded at stations having almost the same distance from the sources do not show a strong dependence on the backazimuth. These results suggest that the decrease of Q 1 with depth is more significant than its lateral variations. Regarding its frequency dependence, Q 1 almost linearly decreases with frequency. Finally, the near-surface-attenuation parameter k is evaluated at 12 stations and the results discussed in terms of site, event, and propagation contributions. The event contribution is not negligible and shows a significant positive correlation with magnitude. The site term is smaller than 0.020 sec for rock or topographic sites, while it assumes values of 0.036 sec and 0.042 sec for two stations installed over thick soft sedimentary layers.
    Beschreibung: Published
    Beschreibung: 188-199
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): waves propagating ; 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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  • 75
    Publikationsdatum: 2017-04-04
    Beschreibung: Tectonic stress in the Pacific Northwest Washington is dominated by a N-S major compressive axis s1 and a minor compressive axis s3 which varies from E-W to near vertical. Minor variations in this pattern occur in different parts of the region. In this study we used ca. 550 earthquakes in the central Washington Cascade Mountains to study in detail the uniformity of the stress tensor in this volcanic arc. Earthquakes from the Pacific Northwest Seismograph Network (PNSN) catalogue were divided into several subsets based on epicentral and depth groupings and stress-tensor inversions using the Gephart and Forsyth technique were computed for each group. As in previous similar studies the maximum compressive stress axis (s1) is nearly horizontal and trending ca. N-S and NNE-SSW in all but one subset. Shallower events directly under Mount Rainier have a near vertical s1. For other subsets the minimum compressive stress axis (s3) deviates from vertical to horizontal for different groups of events. In particular, events in the depth range of 10-14 km in the Western Rainier Seismic Zone (WRSZ) have near vertical s3 direction while other depth ranges in this area show a near horizontal, E-W s3 orientation. We hypothesize that the change in orientation of 3 for the 10-14 km depth range in the WRSZ is probably due to the influence of the nearby Mount Rainier magmatic system.
    Beschreibung: Published
    Beschreibung: 811-821
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): focal mechanism ; stress tensor ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 76
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: The new Italian National Seismic Network (INSN) is a dense network of broadband stations deployed for monitoring Italian seismicity. The network consists of 250 stations with a typical station spacing of !40 km. Earthquake early warning is the rapid detection of an event in progress, assessment of the hazard it poses, and transmission of a warning ahead of any significant ground motion. We explore the potential for using the INSN real-time network for the purpose of earthquake early warning. We run the ElarmS early warning methodology off-line using a data set of more than 200 events with magnitudes between 2.5 and 6.0. A scaling relation for magnitude determination from the dominant period of the first seconds of signal following the P onset is developed from the data set. The standard deviation in the magnitude estimates using this approach is 0.4 magnitude units, and all event magnitude estimates are within !0:75 magnitude units of the true magnitude. Given the existing distribution of seismic stations it takes an average of 10 sec after event initiation before the P wave has been detected at four stations. If we require a detection at four stations before issuing the first alert, then the blind zone, within which no warning would be available, has a radius of !37 km. The ElarmS methodology can provide a warning earlier than this but with a greater uncertainty. An assessment of past damaging earthquakes across Italy shows that applying ElarmS with the existing seismic network could provide warning to population centers in repeats of past events. For example, in a repeat of the 1980 Irpinia earthquake Naples could receive an !15- sec warning. The variations in the size of the blind zone and warning times for different regions can be used as a guide to selecting strategic locations for future station deployments.
    Beschreibung: Published
    Beschreibung: 495-503
    Beschreibung: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Early Warning ; Earthquake Location ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 77
    facet.materialart.
    Unbekannt
    Seismological Society of America
    Publikationsdatum: 2017-04-04
    Beschreibung: The aim of this work is to infer the slip distribution and rupture velocity along the rupture zone of the 26 December 2004 Sumatra–Andaman earthquake from available tide gage records of the tsunami. We selected waveforms from 14 stations, distributed along the coast of the Indian Ocean. Then we subdivided the fault plane into 16 subfaults (both along strike and downdip) following the geometry and mechanism proposed by Banerjee et al. (2005) and computed the corresponding Green’s functions by numerical solution of the shallow-water equations through a finitedifference method. The slip distribution and rupture velocity were determined simultaneously by means of a simulated annealing technique. We compared the recorded and synthetic waveforms in the time domain, using a cost function that is a trade-off between the L1 and L2 norms. Preliminary tests on a synthetic dataset, together with a posteriori statistical analysis of the model ensemble enabled us to assess the effectiveness of the method and to quantify the model uncertainty. The main finding is that the best source model features a nonuniform distribution of coseismic slip, with high slip values concentrated into three main patches: the first is located in the southern part of the fault, off the coast of the Aceh Province; the second between 6.5 N and 11 N; and the third at depth, between 11 N and 14 N. Furthermore, we estimated that the rupture propagated at an average speed of 2.0 km/sec.
    Beschreibung: Published
    Beschreibung: S223-S231
    Beschreibung: 3.1. Fisica dei terremoti
    Beschreibung: JCR Journal
    Beschreibung: partially_open
    Schlagwort(e): Sumatra ; earthquake ; inversion ; tsunami ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 78
    Publikationsdatum: 2017-04-04
    Beschreibung: With the aim to find a more objective way to detect seismic families, we applied a series of successive steps to constrain the results of a waveform similarity analysis. The evaluation of similarity was carried out on the waveforms recorded in the period 1999–2003 by the stations operating in the Garfagnana area, located in northern Tuscany (Italy). The algorithm is based on the cross-correlation technique applied in a process that overcomes the limit of one order of magnitude between events to be compared through a bridging technique. In practice, if two couples of events (A, B) and (B, C), each exceeding the correlation threshold, share a common quake (B), then all three events are attributed to the same family even if the match between A and C is below a value chosen as a reference for similarity. To avoid any subjective choice of threshold for cross-correlation values, the results from the computation algorithm are submitted to a routine that gives increasing reliability to them if they are confirmed by the three components of the seismogram and if the number of families detected by each station is confirmed by more recordings. This latter constraint is made possible by the geometry of the recording network, with interdistances between stations of the order of 40–50 km. The process finally leads to the recognition of 27 families detected and confirmed by, on average, 3 stations that represent 40% of the recording capabilities. Since the performances of the recording network have been very odd in the past, especially in the early years of operation, the reliability of the detection is much higher, as in most cases the stations that detected the families were the only ones to be effectively recording. The methodology proved to be more efficient than other methods applied in the past; moreover, the results could be probably improved even more if, instead of doing a one-run process, it would be borne as a trial-and-error approach.
    Beschreibung: Published
    Beschreibung: 1903-1915
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Seismicity ; multiplets ; seismic families ; seismic sequences ; 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::04.06.09. Waves and wave analysis
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 79
    Publikationsdatum: 2017-04-04
    Beschreibung: The source of repeating earthquakes on creeping faults is modeled as a weak asperity at a border between much larger locked and creeping patches on the fault plane. The x^(-1/2) decrease in stress concentration with distance x from the boundaryis shown to lead directly to the observed scaling 〈T〉~〈M0〉^(1/6) between the average repeat time and average scalar moment for a repeating sequence. The stress drop in such small events at the border depends on the size of the large locked patch. For a circular patch of radius R and representative fault parameters, Dr = 7.6(m/R)3/5 MPa, which yields stress drops between 0.08 and 0.5 MPa (0.8–5 bars) for R between 2 km and 100 m. These low stress drops are consistent with estimates of stress drop for small earthquakes based on their seismic spectra. However, they are orders of magnitude smaller than stress drops calculated under the assumption that repeating sources are isolated stuck asperities on an otherwise creeping fault plane, whose seismic slips keep pace with the surrounding creep rate. Linear streaks of microearthquakes observed on creeping fault planes are trivially explained by the present model as alignments on the boundaries between locked and creeping patches.
    Beschreibung: NSF grants NSF-EAR-9902901 (CGS) and EAR-9805182 (JRR)
    Beschreibung: Published
    Beschreibung: 532-537
    Beschreibung: open
    Schlagwort(e): 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
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article , article
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  • 80
    Publikationsdatum: 2017-04-04
    Beschreibung: A small aperture quadripartite seismic array was installed on the south-east flanks of Mt. Vesuvius about 1 km far from the crater axis, in order to improve the seismic monitoring of this active volcano. The array has the following main purposes: i) to discriminate natural-source generated signals by artificial-source-generated signals; ii) to detect and track the source of possible Long Period (LP) events; iii) to detect coherent phases in the low frequency noise that may be related to magma movements (tremor insurgence). In addition, the array greatly helps in locating the seismic signals produced by blasts (both in land and sea), allowing a fast discrimination of possible natural long period (LP) quakes. The array is also an useful tool for retrieving the kinematic properties of the wavefield associated to volcano-tectonic (VT) earthquakes (more than 99% of the whole natural seismicity) and to all the other transients which are routinely observed(landslides, artificial blasts). We also use the array to investigate if correlated signals are present in the background noise (insurgence of volcanic tremor). The main result obtained during this first year of observation is that one LP was clearly recognized in the background seismicity at Mt. Vesuvius.
    Beschreibung: Published
    Beschreibung: 344-355
    Beschreibung: open
    Schlagwort(e): Volcano monitoring ; Array techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 81
    Journal cover
    Unbekannt
    Wiley | JSTOR | formerly Oxford University Press (OUP)
    Online: 10(1).1988 –
    Vormals: Illinois Agricultural Economics; North Central Journal of Agricultural Economics; Review of Agricultural Economics  (1961–2009)
    Verlag: Wiley , JSTOR , formerly Oxford University Press (OUP)
    Print ISSN: 0191-9016 , 1058-7195 , 2040-5790
    Digitale ISSN: 1467-9353 , 2040-5804
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Wirtschaftswissenschaften
    Schlagwort(e): JSTOR Archive Collection Business II
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Journal cover
    Unbekannt
    Wiley | JSTOR
    Online: 78.1976 – (older than 6 years)
    Verlag: Wiley , JSTOR
    Print ISSN: 0347-0520
    Digitale ISSN: 1467-9442
    Thema: Wirtschaftswissenschaften
    Schlagwort(e): JSTOR Archive Collection Business II
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  • 83
    Journal cover
    Unbekannt
    Wiley | Financial Management Association International | JSTOR
    Online: 1(1).1972 – (older than 4 years)
    Verlag: Wiley , Financial Management Association International , JSTOR
    Print ISSN: 0046-3892
    Digitale ISSN: 1755-053X
    Thema: Wirtschaftswissenschaften
    Schlagwort(e): JSTOR Archive Collection Business II
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