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  • 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk  (23)
  • 04.06. Seismology  (15)
  • 04.04. Geology
  • Antarctic bacterioplankton
  • Seismological Society of America  (35)
  • American Institute of Physics (AIP)
  • Nature Publishing Group
  • Wiley
Collection
  • 1
    Publication Date: 2024-02-07
    Description: A catalogue of precisely located micro-seismicity is fundamental for investigating seismicity and rock physical properties in active tectonic and volcanic regions and for the definition of a ‘baseline’ seismicity, required for a safe future exploitation of georesource areas. In this study, we produce the first manually revised catalogue of micro-seismicity for Co. Donegal region (Ireland), an area of about 50K M2 of on-going deformation, aimed at localizing natural micro-seismic events occurred between 2012 and 2015. We develop a stochastic method based on a Markov chain Monte Carlo (McMC) sampling approach to compute earthquake hypocentral location parameters. Our results indicates that micro-seismicity is present with magnitudes lower than 2 (the highest magnitude is 2.8).The recorded seismicity is almost clustered along previously mapped NE-SW trending, steeply dipping faults and confined within the upper crust (focal depth less than 10 km). We also recorded anthropogenic seismicity mostly related to quarries' activity in the study area.
    Description: Published
    Description: 62-76
    Description: OST1 Alla ricerca dei Motori Geodinamici
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2024-04-09
    Description: Underdetermination is a condition affecting all problems in seismic imaging. It manifests mainly in the nonuniqueness of the models inferred from the data. This condition is exacerbated if simplifying hypotheses like isotropy are discarded in favor of more realistic anisotropic models that, although supported by seismological evidence, require more free parameters. Investigating the connections between underdetermination and anisotropy requires the implementation of solvers which explore the whole family of possibilities behind nonuniqueness and allow for more informed conclusions about the interpretation of the seismic models. Because these aspects cannot be investigated using traditional iterative linearized inversion schemes with regularization constraints that collapse the infinite possible models into a unique solution, we explore the application of transdimensional Bayesian Monte Carlo sampling to address the consequences of underdetermination in anisotropic seismic imaging. We show how teleseismic waves of P and S phases can constrain upper‐mantle anisotropy and the amount of additional information these data provide in terms of uncertainty and trade‐offs among multiple fields.
    Description: In press
    Description: OST1 Alla ricerca dei Motori Geodinamici
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
    Publication Date: 2024-03-12
    Description: The macroseismic source parameters of earthquakes occurring within a sequence are strongly influenced by cumulative damage effects. When we deal with historical seismic sequences, in addition to the cumulative intensities, other intrinsic uncertainties due to the scarcity and indeterminacy of sources come into play. These issues imply that the parameterizations of the single earthquakes within a historical seismic sequence are not univocal and that all the uncertainties that are addressed when assessing macroseismic intensity should be carefully considered in the parameter estimation. In the light of these considerations, we performed some tests on the 2016–2017 and 1703 seismic sequences, which occurred in the same area in central Italy, to compute the macroseismic source parameters by means of two independent methods. Results show that the cumulative effects arising from multiple damaging earthquakes can cause biases in the intensity assessments, which affect the computed magnitude and epicentral locations. To reduce bias in macroseismic intensities due to cumulative damage, we illustrate a simple procedure, called cumulative intensity subtraction (CIS), which consists in discarding the localities strongly damaged by the early earthquakes of a sequence from the intensity distributions used for computing the macroseismic source parameters of the subsequent earthquakes. The outcomes show that, for the 2016 seismic sequence, the CIS approach provides locations in agreement with the instrumental epicenters and with the causative faults. For the 1703 sequence, the CIS approach along with explicit accounting for the indeterminacy in intensity assignments give a range of equally plausible solutions. The CIS represents an exploration of a simple strategy that stems from an attempt to give significance to macroseismic intensity in the presence of cumulative damage.
    Description: Published
    Description: 759–774
    Description: OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impatto
    Description: JCR Journal
    Keywords: macroseismic intesity ; cumulative effects ; microseismic source parameters ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    Seismological Society of America
    In:  Das, R., M. L. Sharma, H. R. Wason, D. Choudhury, and G. Gonzales (2019). A seismic moment magnitude scale, Bull Seismol. Soc. Am. 109, no. 4, 1542–1555, doi: 10.1785/0120180338.
    Publication Date: 2024-05-21
    Description: Moment magnitude Mw was first defined by Hiroo Kanamori in the late 1970s, when the availability of new force balance seismometers made it possible to measure the seismic moment M0 with virtually no limits in the frequency passband. For this reason, Mw does not become saturated even for the largest earthquakes ever recorded. Mw has been chosen in such a way that it coincides best with the previous definitions of magnitude (Ms, ML, mb, etc.) on certain ranges of values but can deviate significantly from them within other ranges. A few years ago, Das and colleagues proposed a new moment magnitude scale Mwg with the aim of better reproducing the values of mb and Ms over their entire range and to better predict the energy ES radiated by earthquakes. We show that there was no need to define such a new scale and that Mwg is not even optimal to achieve the goal of matching ES.
    Description: In press
    Description: OST2 Deformazione e Hazard sismico e da maremoto
    Description: JCR Journal
    Keywords: earthquake magnitude ; moment magnitude scale ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
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    Seismological Society of America
    In:  "Earthquake Magnitude Conversion Problem” by Ranjit Das, H. R. Wason, Gabriel Gonzalez, M. L. Sharma, Deepankar Choudhury, Conrad Lindholm, Narayan Roy, and Pablo Salazar
    Publication Date: 2024-05-21
    Description: Similar to the previous ones, the latest paper by Das and Colleagues (Das et al.,2018) on the application of the general orthogonal regression (GOR) method (Fuller, 1987; Castellaro et al.,2006), for the conversions between different types of earthquake magnitudes, is a collection of incorrect or undemonstrated assertions, most of which have already been pointed out in several contributions that have been published in the last few years (Gasperini and Lolli, 2014a, b; Gasperini et al., 2015, 2018; Pujol, 2018). We recall below only some of them. According to the recent seismological literature, we use here the term “GOR” to indicate the errors-in variable regression method described by Fuller (1987), even if such term is not fully in line with mathematical statistics as orthogonality is only given for equal errors of the dependent and independent variables.
    Description: Published
    Description: 1366-1369
    Description: OST2 Deformazione e Hazard sismico e da maremoto
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publication Date: 2024-05-22
    Description: We present a new approach to estimate the predominant direction of rupture propagation during a seismic sequence. A fast estimation of the rupture propagation direction is essential to knowthe azimuthal distribution of shaking around the seismic source and the associated risks for the earthquake occurrence. The main advantage of the proposed method is that it is conceptually reliable, simple, and fast (near real time). The approach uses the empirical Green’s function technique and can be applied directly to the waveforms without requiring the deconvolution of the instrumental response and without knowing a priori the attenuation model and the orientation of the activated fault system. We apply the method to the 2016–2017 Amatrice-Visso-Norcia high-energy and long-lasting earthquake series in central Italy,which affected a large area up to 80 kmalong strike, withmore than 130,000 events of small-to-moderate magnitude recorded until the end of August 2022. Most of the selected events analyzed in this study have a magnitude greater than 4.4 and only four seismic events have a magnitude in the range of 3.3–3.7. Our results show that the complex activated normal fault system has a rupture direction mainly controlled by the pre-existing normal faults and by the orientation of the reactivated faults. In addition, the preferred direction of rupture propagation is also controlled by the presence of fluid in the pre-existing structural discontinuities. We discuss the possible role of fluids as a cause of bimaterial interface. Another important finding from our analysis is that the spatial evolution of seismicity is controlled by the directivity.
    Description: Published
    Description: 1912–1924
    Description: JCR Journal
    Keywords: directivity ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2023-03-31
    Description: We investigate the dependence of the Gutenberg–Richter b parameter on the crustal thickness quantified by the Moho depth, for nine different regional catalogs. We find that, for all the catalogs considered in our study, the b‐value is larger in areas presenting a thicker crust. This result appears in apparent contradiction with previous findings of a b decreasing with the focal depth. However, both the results are consistent with acoustic emission experiments, indicating a b‐value inversely proportion to the applied differential stress. Our results can be indeed interpreted as the signature of a larger stress concentration in areas presenting a thinner crust. This is compatible with the scenario where postseismic deformation plays a central role in stress concentration and in aftershock triggering.
    Description: Published
    Description: 1921–1934
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: b-value ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    Unknown
    Seismological Society of America
    In:  Taroni, M., J. Zhuang, and W. Marzocchi (2021). High-definition mapping of the Gutenberg–Richter b-value and its relevance: A case study in Italy, Seismol. Res. Lett. 92, 3778–3784, doi: 10.1785/0220210017.
    Publication Date: 2023-02-21
    Description: Taroni et al. (2021) published a statistical framework to reliably estimate the b-value and its uncertainties, with the goal being the interpretation in a seismotectonic context and improving earthquake forecasting capabilities. In this comment, we show that the results presented for the Italian region and the conclusions drawn by the authors, are heavily biased due to quarry-blast events in the Italian earthquake catalog used in the analysis. Without removing this anthropogenic component in the data, a meaningful analysis of the earthquake- size distribution for natural seismicity is, in our opinion, not possible. This comment highlights the need for basic data quality analysis before sophisticated statistical tools are applied to a dataset.
    Description: European Union’s Horizon 2020 research and innovation program under Grant Agreement Number 821115 Pianeta Dinamico-Working Earth INGV-MUR project.
    Description: Published
    Description: 1089-1094
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2023-10-03
    Description: In part 1, we run multiple GIT decomposition for different choices of model assumptions, namely three different window duration for Fourier calculation, two different parametrization of the attenuation, two different site constraints. We also considered different source models (Brune, Boatwright, Brune with kappa_source) and different approaches to estimate uncertainties of source parameters (i.e., considering the covariance matrix, Monte Carlo sampling of the residual distribution, model selection with threshold based on F-test).
    Description: As part of the community stress-drop validation study initiative, we apply a spectral decomposition approach to isolate the source spectra of 556 events occurred during the 2019 Ridgecrest sequence (Southern California). We perform multiple decompositions by introducing alternative choices for some processing and model assumptions, namely: three different S-wave window durations (i.e., 5 s, 20 s, and variable between 5 and 20 s); two attenuation models that account differently for depth dependencies; and two different site amplification constraints applied to restore uniqueness of the solution. Seismic moment and corner frequency are estimated for the Brune and Boatwright source models, and an extensive archive including source spectra, site amplifications, attenuation models, and tables with source parameters is disseminated as the main product of the present study. We also compare different approaches to measure the precision of the parameters expressed in terms of 95% confidence intervals (CIs). The CIs estimated from the asymptotic standard errors and from Monte Carlo resampling of the residual distribution show an almost one-to-one correspondence; the approach based on model selection by setting a threshold for misfit chosen with an F-ratio test is conservative compared to the approach based on the asymptotic standard errors. The uncertainty analysis is completed in the companion article in which the outcomes from this work are used to compare epistemic uncertainty with precision of the source parameters.
    Description: Published
    Description: 1980–1991
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: source parameters ; GIT ; uncertainties ; moment magnitude ; corner frequency ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2023-01-23
    Description: The detection level of a seismic network is a measure of its effective ability to record small earthquakes in a given area. It can vary in both space and time and depends on several factors such as meteorological conditions, anthropic noise, local soil conditions—all factors that affect the seismic noise level—as well as the quality and operating condition of the instruments. The ability to estimate the level of detection is of tremendous importance both in the design of a new network and in determining whether a given network can recognize seismicity consistently or needs to be improved in some of its parts. In this article, we determine the detection level of the Cuban seismic network using the empirically estimated seismic noise spectral level at each station site and some theoretical relationships to predict the signal amplitude of a seismic event at individual stations. The minimum local detectable magnitude thus depends on some network parameters such as the signal‐to‐noise ratio and the number of stations used in the calculation. We also demonstrate the effectiveness of our predictions by comparing the estimated detection level with those empirically determined from one year of data (i.e., the year 2020) of the Cuban seismic catalog. Our analysis shows, on the one hand, in which areas the current Cuban network should be improved, also depending on the regional pattern of faults, and, on the other hand, indicates the magnitude threshold that can be assumed homogeneously for the catalog of Cuban earthquakes in 2020. Because the adopted method can use current measurements of the seismic noise level (e.g., daily), the proposed analysis can also be configured for continuous monitoring of network state quality.
    Description: Published
    Description: 2048-2062
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: 1IT. Reti di monitoraggio e sorveglianza
    Description: JCR Journal
    Keywords: seismic monitoring ; detection ; cuba ; seismic network ; Event Detection Level ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2023-03-01
    Description: Minimum 1D velocity models and station corrections have been computed for the central Mediterranean area using two main data sets. The first one consists of accurate first arrival‐time readings from 103 seismic events with magnitude (ML)≥3.5 recorded by the Italian National Seismic Network (RSN) and the AlpArray Seismic Network (AASN) in the period 2014–2021. Earthquakes were selected on the basis of their spatial distribution, epicentral distance to the nearest seismic station, and maximum distance traveled by Pn and Sn phases. This fine selection of high‐quality data combined with the spatial density of the AlpArray seismic stations was decisive in obtaining high resolution for upper mantle velocity, especially in the Alpine belt. To obtain a denser coverage of crustal rays, we extended the first data set with P and S arrivals of local earthquakes from Istituto Nazionale di Geofisica e Vulcanologia (INGV) bulletin data (2016–2018). A total of 75,807 seismic phases (47,183 P phases and 28,264 S phases) have been inverted to calculate best‐fit 1D velocity models, at regional and local scales. We then test the performance of the optimized velocity models by relocating the last four years of seismicity recorded by INGV (period 2017–2020). The computed velocity models are very effective for routine earthquake location, seismic monitoring, source parameter modeling, and future 3D seismic tomography.
    Description: Published
    Description: 2670--2685
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: geophysics ; velocity models ; Italian seismicity ; central mediterranean area ; 04. Solid Earth ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2022-10-31
    Description: The statistical properties of seismicity are known to be affected by several factors such as the rheological parameters of rocks. We analysed the earthquake double-couple as a function of the faulting type. Here we show that it impacts the moment tensors of earthquakes: thrust- faulting events are characterized by higher double-couple components with respect to strike- slip- and normal-faulting earthquakes. Our results are coherent with the stress dependence of the scaling exponent of the Gutenberg-Richter law, which is anticorrelated to the double- couple. We suggest that the structural and tectonic control of seismicity may have its origin in the complexity of the seismogenic source marked by the width of the cataclastic damage zone and by the slip of different fault planes during the same seismic event; the sharper and concentrated the slip as along faults, the higher the double-couple. This phenomenon may introduce bias in magnitude estimation, with possible impact on seismic forecasting.
    Description: Published
    Description: 258
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: double couple ; damage zone ; different fault type ; seismicity ; tectonics ; fault type ; seismicity ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2022-06-22
    Description: Silicic calderas are volcanic systems whose unrest evolution is more unpredictable than other volcano types because they often do not culminate in an eruption. Their complex structure strongly influences the post-collapse volcano-tectonic evolution, usually coupling volcanism and ground deformation. Among such volcanoes, the Campi Flegrei caldera (southern Italy) is one of the most studied. Significant long- and short-term ground deformations characterize this restless volcano. Several studies performed on the marinecontinental succession exposed in the central sector of the Campi Flegrei caldera provided a reconstruction of ground deformation during the last 15 kyr. However, considering that over one-third of the caldera is presently submerged beneath the Pozzuoli Gulf, a comprehensive stratigraphic on-land-offshore framework is still lacking. This study aims at reconstructing the offshore succession through analysis of high-resolution single and multichannel reflection seismic profiles and correlates the resulting seismic stratigraphic framework with the stratigraphy reconstructed on-land. Results provide new clues on the causative relations between the intra-caldera marine and volcaniclastic sedimentation and the alternating phases of marine transgressions and regressions originated by the interplay between ground deformation and sea-level rise. The volcano-tectonic reconstruction, provided in this work, connects the major caldera floor movements to the large Plinian eruptions of Pomici Principali (12 ka) and Agnano Monte Spina (4.55 ka), with the onset of the first post-caldera doming at ~10.5 ka. We emphasize that ground deformation is usually coupled with volcanic activity, which shows a self-similar pattern, regardless of its scale. Thus, characterizing the long-term deformation history becomes of particular interest and relevance for hazard assessment and definition of future unrest scenarios.
    Description: Published
    Description: 855-882
    Description: 1V. Storia eruttiva
    Description: JCR Journal
    Keywords: offshore stratigraphy ; seismic units ; La Starza succession ; volcanism, ; 04.08. Volcanology ; 04.04. Geology ; 04.07. Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
    Publication Date: 2020-05-25
    Description: We explore the three‐dimensional structure of the 2016–2017 Central Italy sequence using ~34,000 ML ≥ 1.5 earthquakes that occurred between August 2016 and January 2018. We applied cross‐correlation and double‐difference location methods to waveform and parametric data routinely produced at the Italian National Institute of Geophysics and Volcanology. The sequence activated an 80 km long system of normal faults and near‐horizontal detachment faults through the MW 6.0 Amatrice, the MW 5.9 Visso, and the MW 6.5 Norcia mainshocks and aftershocks. The system has an average strike of N155°E and dips 38°–55° southwestward and is segmented into 15–30 km long faults individually activated by the cascade of MW ≥ 5.0 shocks. The two main normal fault segments, Mt. Vettore‐Mt. Bove to the North and Mt. della Laga to the South, are separated by an NNE‐SSW‐trending lateral ramp of the Sibillini thrust, a regional structure inherited from the previous compressional tectonic phase putting into contact diverse lithologies with different seismicity patterns. Space‐time reconstruction of the fault system supports a composite rupture scenario previously proposed for the MW 6.5 Norcia earthquake, where the rupture possibly propagated also along an oblique portion of the Sibillini thrust. This dissected set of normal fault segments is bounded at 8–10 km depth by a continuous 2 km thick seismicity layer of extensional nature slightly dipping eastward and interpreted as a shear zone. All three mainshocks in the sequence nucleated along the high‐angle planes at significant distance from the shear zone, thus complicating the interpretation of the mechanisms driving strain partitioning between these structures.
    Description: Published
    Description: e2019JB018440
    Description: 3T. Sorgente sismica
    Description: JCR Journal
    Keywords: normal fault ; shear zone ; fault segmentation ; apennines ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
    Publication Date: 2020-07-08
    Description: 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.
    Description: Italian Ministry for Education, University, and Research (MIUR), Premiale 2014 D. M. 291 03/05/2016.
    Description: Published
    Description: e2020TC006116
    Description: 2T. Deformazione crostale attiva
    Description: 2TR. Ricostruzione e modellazione della struttura crostale
    Description: JCR Journal
    Keywords: 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)
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  • 16
    Publication Date: 2021-01-25
    Description: Tsunami deposits present an important archive for understanding tsunami histories and dynamics. Most research in this field has focused on onshore preserved remains, while the offshore deposits have received less attention. In 2009, during a coring campaign with theItalian Navy Magnaghi, four 1 m long gravity cores (MG cores) were sampled from the northern part of Augusta Bay, along a transect in 60 to 110 m water depth. These cores were taken in the same area where a core (MS06) was collected in 2007 about 2.3 km offshore Augusta at a water depth of 72 m below sea level. Core MS06 consisted of a 6.7 m long sequence that included 12 anomalous intervals interpreted as the primary effect of tsunami backwash waves in the last 4500 years. In this study, tsunami deposits were identified, based on sedimentology and displaced benthic foraminifera (as for core MS06) reinforced by X-ray fluorescence data. Two erosional surfaces (L1 and L2) were recognized coupled with grain size increase, abundant Posidonia oceanica seagrass remains and a significant amount of Nubecularia lucifuga, an epiphytic sessile benthic foraminifera considered to be transported from the inner shelf. The occurrence of Ti/Ca and Ti/Sr increments, coinciding with peaks in organic matter (Mo inc/coh) suggests terrestrial run-off coupled with an input of organic matter. The L1 and L2 horizons were attributed to two distinct historical tsunamis (AD 1542 and AD 1693) by indirect age-estimation methods using 210Pb profiles and the comparison of Volume Magnetic Susceptibility data between MG cores and MS06 cores. One most recent bioturbated horizon (Bh), despite not matching the above listed interpretative features, recorded an important palaeoenvironmental change that may correspond to the AD 1908 tsunami. These findings reinforce the value of offshore sediment records as an underutilized resource for the identification of past tsunamis.
    Description: Published
    Description: 1553-1576
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Eastern Sicily ; tsunami ; foraminifera ; sedimentology ; XRF core scanning ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
    Publication Date: 2018-02-16
    Description: In the last two decades, several studies addressed the revaluation and homogenization of the Italian instrumental seismic catalog, but all of them refer to the time interval from 1981, that is, the starting year of the Catalogo Strumentale dei Terremoti Italiani (CSTI). At the time, the CSTI was conceived as the continuation of the catalog of the Progetto Finalizzato Geodinamica (PFG) but, over time, the PFG catalog was almost totally forgotten, and presently it is even difficult to obtain because it is not provided by any website. In this work, we integrate a genuine copy of PFG, with additional locations from the bulletins of the Istituto Nazionale di Geofisica (ING, now known as INGV) and of the International Seismological Centre (ISC) and with local magnitudes from two couples of Wood–Anderson (WA) seismometers operational in Italy in the 1970s and 1980s, mostly derived from a careful scrutiny of paper bulletins of the Osservatorio Geofisico Sperimentale (OGS) and of the ING. We restrict our analysis to the time interval from 1960 to 1980 because, based on various evidence, we can infer that within such period most instrumental magnitudes reported by the PFG catalog are reasonably coherent with the Richter’s definition. Magnitudes provided by WA stations and other data sources are calibrated with respect to Mw by general orthogonal regressions. The final catalog from 1960 to 1980 contains 8536 earthquakes, of which we compute a true or proxy Mw magnitude with related uncertainty for 6407. The analysis of the frequency–magnitude distribution indicates completeness for about Mw ≥4:0. This work extends the time coverage of the Italian instrumental catalog to about 55 yrs before the present, allowing the statistical study of some important seismic periods that occurred, for example, in 1962 (Irpinia), 1968 (Belice Valley), 1976 (Friuli), 1979 (Umbria), and 1980 (Irpinia).
    Description: Published
    Description: 481–492
    Description: 4IT. Banche dati
    Description: JCR Journal
    Keywords: local magnitude ; magnitude homogenization ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2021-11-08
    Description: Seismicity during Dutch colonial rule in Indonesia between 1800 and 1939 is poorly catalogued with existing summaries (e.g. Newcomb & McCann, 1987) too brief for further quantitative assessment such as the calculation of intensity magnitudes (MI). We focus on this period in Indonesian history, collating and analysing reports from official documents and newspapers from the erstwhile Dutch East Indies. We scrutinize these for macroseismic intensity using the European Macroseismic Scale (EMS-98). This scale is closely related to the Modified Mercalli Intensity (MMI) scale but is associated with better guidelines with which to assess damage to built-up environments. Our approach enables us to uniformly assess felt intensities from Sumatra, Java, Bali, and Borneo along with instances of perceived shaking from the eastern Indonesian archipelago, and from the Malay peninsula including Singapore. Building upon previous work (Martin et al., 2015), we corelate our data, when possible, with regional, and teleseismic instrumental observations. This allows us to discriminate, for example, a possible M~6 doublet in the region of South Sumatra in 1908. Felt effects in west Malaysia and Singapore from numerous earthquakes in Sumatra were also collected, and unexpectedly, we found two widely felt earthquakes in Singapore in 1922 that likely originated in the region of the southern Malaya peninsula. All our observations contribute to a database named Gempa Nusantara which roughly translates to earthquakes (gempa) in the Indonesian archipelago (nusantara) in Bahasa Indonesia. This database uses a web application called MIDOP (Macroseismic Intensity Data Online Publisher) which is an open-source program written in PHP that has been previously utilized to publish intensity data in Europe (Locati et al., 2014). In our study we extend the capabilities of the MIDOP application further, particularly in equatorial regions, and use it to manage our data from historical Indonesian earthquakes.
    Description: Earth Observatory of Singapore, Nanyang Technological University
    Description: Published
    Description: Miami, Florida, United States of America
    Description: 4T. Sismicità dell'Italia
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Keywords: historical seismology ; macroseismic intensity ; 04. Solid Earth ; 04.04. Geology ; 04.06. Seismology ; 05.02. Data dissemination
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
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  • 19
    Publication Date: 2021-06-21
    Description: The seismological community is currently developing operational earthquake forecasting (OEF) systems that aim to estimate, based on continuous ground motion recording by seismic networks, the rates of events exceeding a certain magnitude threshold in an area of interest and in a short-period of time (days to weeks); i.e., the seismicity. OEF may be possibly used for short-term seismic risk management in regions affected by seismic swarms only if its results may be the input to compute, in a probabilistically sound manner, consequence-based risk metrics. The present paper reports the investigation about feasibility of short-term risk assessment, or operational earthquake loss forecasting (OELF), in Italy. The approach is that of performance-based earthquake engineering, where the loss rates are computed by means of hazard, vulnerability, and exposure. The risk is expressed in terms of individual and regional measures, which are based on short-term macroseismic intensity, or ground motion intensity, hazard. The vulnerability of the built environment relies on damage probability matrices empirically calibrated for Italian structural classes, and exposure data in terms of buildings per vulnerability class and occupants per building typology. All vulnerability and exposure data are at the municipality scale. The procedure set-up, which is virtually independent on the seismological model used, is implemented in an experimental OELF system, which continuously process OEF information to produce weekly nationwide risk maps. This is illustrated by a retrospective application to the 2012 Pollino (southern Italy) seismic sequence, which provides insights on the capabilities of the system and on the impact, on short-term risk assessment, of the methodology currently used for OEF in Italy.
    Description: Published
    Description: 2286-2298
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: operational earthquake forecasting ; seismic risk ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 20
    Publication Date: 2021-05-12
    Description: Any trustworthy probabilistic seismic hazard analysis (PSHA) has to account for the intrinsic variability of the system (aleatory variability) and the limited knowledge of the system itself (epistemic uncertainty). The most popular framework for this purpose is the logic tree. Notwithstanding its vast popularity, the logic tree outcomes are still interpreted in two different and irreconcilable ways. In one case, practitioners claim that the mean hazard of the logic tree is the hazard and the distribution of all outcomes does not have any probabilistic meaning. On the other hand, other practitioners describe the seismic hazard using the distribution of all logic tree outcomes. In this paper, we explore in detail the reasons of this controversy about the interpretation of logic tree, showing that the distribution of all outcomes is more appropriate to provide a joined full description of aleatory variability and epistemic uncertainty. Then, we provide a more general framework - that we name ensemble modeling - in which the logic tree outcomes can be embedded. In this framework, the logic tree is not a classical probability tree, but it is just a technical tool that samples epistemic uncertainty. Ensemble modeling consists of inferring the parent distribution of the epistemic uncertainty from which this sample is drawn. Ensemble modeling offers some remarkable additional features. First, it allows a rigorous and meaningful validation of any PSHA; this is essential if we want to keep PSHA into a scientific domain. Second, it provides a proper and clear description of the aleatory variability and epistemic uncertainty that can help stakeholders to appreciate the whole range of uncertainties in PSHA. Third, it may help to reduce the computational time when the logic tree becomes computationally intractable because of the too many branches.
    Description: Published
    Description: 2151-2159
    Description: 1SR. TERREMOTI - Servizi e ricerca per la Società
    Description: JCR Journal
    Description: reserved
    Keywords: seismic hazard ; logic tree ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 21
    Publication Date: 2021-06-22
    Description: Seismic aftershock-hazard analysis is one of the first steps toward estab- lishing an integrated risk-based decision-making support framework for emergency management in the event of an ongoing aftershock sequence. This work focuses on providing adaptive daily forecasts of the mean daily rate of exceeding various spectral acceleration values (the aftershock hazard). Two well-established earthquake- occurrence models suitable for daily seismicity forecasts associated with the evolution of an aftershock sequence, namely, the modified Omori’s aftershock model (MO) and the epidemic-type aftershock sequence (ETAS) are adopted. An adaptive and evolution- ary MO-based aftershock occurrence model with distinct spatial and temporal compo- nents is proposed. In this model, the parameters deciding the temporal decay are updated based on the data provided by the ongoing aftershock sequence. This model adopts an evolutionary spatial seismicity pattern loosely based on spatial clustering of aftershock events in the sequence. Bayesian updating is also employed to provide sequence-based parameter estimates for a given ground-motion prediction model. Daily forecasts of the mean rate of exceedance of various spectral acceleration levels are calculated based on alternative occurrence models and the updated ground-motion prediction relation. As a numerical example, daily forecasts of the aftershock-hazard curve are obtained for the L’Aquila aftershock sequence based on the MO-based and ETAS occurrence models, and an updated version of the Sabetta and Pugliese (1996) ground-motion prediction model. These daily hazard forecasts are then compared with the observed daily rates of exceeding various spectral acceleration thresholds.
    Description: Published
    Description: 145 – 161
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: earthquake forecast ; aftershock ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 22
    Publication Date: 2021-06-25
    Description: We cannot yet predict large earthquakes in the short term with much reliability and skill, but the strong clustering exhibited in seismic sequences tells us that earthquake probabilities are not constant in time; they generally rise and fall over periods of days to years in correlation with nearby seismic activity. Opera- tional earthquake forecasting (OEF) is the dissemination of authoritative information about these time-dependent proba- bilities to help communities prepare for potentially destructive earthquakes. The goal of OEF is to inform the decisions that people and organizations must continually make to mitigate seismic risk and prepare for potentially destructive earthquakes on time scales from days to decades. To fulfill this role, OEF must provide a complete description of the seismic hazard—ground-motion exceedance probabilities as well as short-term rupture probabilities—in concert with the long-term forecasts of probabilistic seismic-hazard analysis (PSHA).
    Description: Published
    Description: 955-959
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: Operational earthquake forecasting ; seismic preparedness ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 23
    Publication Date: 2017-04-04
    Description: 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.
    Description: 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).
    Description: Published
    Description: 912-927
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: 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)
    Type: article
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  • 24
    Publication Date: 2017-04-04
    Description: On 6 April 2009, an Mw 6.2 earthquake struck beneath the city of L’Aquila, central Italy. The shock created significant damage and caused more than 300 deaths in the city and environs. The event followed a seismic sequence that started at the begin- ning of the year, with its largest shock of M w 4.2 occurring on 30 March. The 6 April earthquake became infamous worldwide because seven experts, who attended a Grandi Rischi Commis- sion meeting on 31 March, were convicted of failing to properly warn the public about the possibility of the mainshock and were sentenced to six years in jail. A second trial is in process. We do not wish to further discuss this important case here (in- stead see Marzocchi, 2012 and the website http://processoaquila .wordpress.com/; last accessed June 2014); however, it illustrates the importance of providing authoritative scientific information about earthquake probabilities to the public and other users and serves as a catalyst for the scientific developments now underway in Italy.
    Description: Published
    Description: 961-969
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: Operational earthquake forecasting ; ensemble modeling ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 25
    facet.materialart.
    Unknown
    Seismological Society of America
    Publication Date: 2017-04-04
    Description: In this paper, we discuss in depth, one of the basic procedures that stands behind probabilistic seismic-hazard analysis (PSHA), that is, the declustering of the seismicity rates. First, we explore the technical, scientific, and practical motivations that led to introducing the declustering of seismicity rates. Then, we show that for PSHA, declustering is essential only to minimize a spatial distortion of the earthquake occurrence process, but, conversely, it may lead to significant underestimation of the true seismic hazard. This underestimation precludes the possibility to test meaning- fully PSHA against real observations, and it may lead to underestimate the seismic risk, whenever seismic-hazard maps are used for risk assessment. Finally, we propose a methodology that can be used in PSHA to avoid this potential bias.
    Description: Published
    Description: 1838-1845
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: seismic hazard ; declustering ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 26
    Publication Date: 2017-04-04
    Description: In their lengthy comment on Stucchi et al. (2011), Mucciarelli and Albarello (2012) propose opinions on aspects of the study that have been discussed and reviewed in countless circumstances in Italy and internationally, from the very beginning (2003) to the end (2009) of our research.
    Description: Published
    Description: 2793-2794
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: Seismic hazard ; Italy ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 27
    Publication Date: 2017-04-04
    Description: 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.
    Description: Published
    Description: 645-655
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: 1.9. Rete GPS nazionale
    Description: 1.10. TTC - Telerilevamento
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: 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)
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  • 28
    Publication Date: 2017-04-04
    Description: The societal importance and implications of seismic hazard assessment forces the scientific community to pay an increasing attention to the evaluation of uncertainty, to provide accurate assessments. Probabilistic Seismic Hazard Assessment (PSHA) formally accounts for the natural variability of the involved phenomena, from seismic sources to wave propagation. Recently, an increasing attention is paid to the consequences that alternative modeling procedures have on hazard results. This uncertainty, essentially of epistemic nature, has been shown to have major impacts on PSHA results, leading to extensive applications of techniques like the Logic Tree. Here, we develop a formal Bayesian inference scheme for PSHA that allows, on one side, to explicitly account for all uncertainties and, on the other side, to consider a larger set of sources of information, from heterogeneous models to past data. This process decreases the chance of undesirable biases, and leads to a controlled increase of the precision of the probabilistic assessment. In addition, the proposed Bayesian scheme allows (i) the assignment of a ’subjective’ reliability to single models, without requirement of completeness or homogeneity, and (ii) a transparent and uniform evaluation of the ’strength’ of each piece of information used on the final results. The applicability of the method is demonstrated through the assessment of seismic hazard in the Emilia-Romagna region (Northern Italy), in which the results of a traditional Cornell-McGuire hazard model based on a Logic Tree are locally updated with the historical macroseismic records, to provide a unified assessment that accounts for both sources of information.
    Description: Published
    Description: 1709-1722
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: restricted
    Keywords: Cornell-McGuire approach ; site intensity ; Bayesian inference ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
    Publication Date: 2017-04-04
    Description: 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.
    Description: Published
    Description: 629-644
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: 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
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  • 30
    Publication Date: 2022-06-09
    Description: In the frame of the Italian research project INGV-DPC S2 (http://nuovoprogettoesse2.stru.polimi.it/), funded by the Dipartimento della Protezione Civile (DPC; National Civil Protection Department) within the agreement 2007-2009, a tool for probabilistic seismic hazard assessment (PSHA) was developed. The main goal of the project was to provide a flexible computational tool for PSHA; the requirements considered essential for the success of the project included: •ability to handle both stationary and non-stationary earthquake time-occurrence models; •ability to use ground-motion prediction models that are not parametric equations but probabilistic "footprints" of the intensities generated by earthquakes of known magnitude and focal characteristics. Usually, these footprints are results of ground motion simulations. Some commonly used programs (e.g., FRISK, by McGuire, 1978; SEISRISK III, by Bender and Perkins, 1987) and more recent and state-of-the-art tools (e.g. OpenSHA, by Field et al., 2003, http://www.opensha.org; OpenQuake, http://openquake.org) for PSHA were analyzed. It was decided to focus on CRISIS2007, which was already a mature and well known application (e.g., Kalyan Kumar and Dodagoudar, 2011; Teraphan et al., 2011; D’Amico et al., 2012; see also http://ecapra.org/CRISIS-2007), but also suitable for additional development and evolution since its source code is freely available on request. The computational tool resulted in an extensive redesign and renovation of the previous CRISIS2007 version. CRISIS is a computer program for PSHA, originally developed in the late 1980's using Fortran as programming language (Ordaz, 1991). In this format, still without a graphical user interface (GUI), it was distributed as part of SEISAN tools (Ottemöller et al., 2011). Ten years later, a GUI was constructed, generating what was called CRISIS99 (Ordaz, 1999). In this version, all the graphic features were written in Visual Basic, but the computation engine remained a Fortran dynamic link library. The reason for the use of mixed-language programming was that computations in Visual Basic were extremely slow. Around 2007 the program was upgraded, in view of the advantages offered by the object-oriented technologies. An object-oriented programming language was required and the natural choice was Visual Basic.Net. In the new version (called CRISIS2007), both the GUI and the computation engine were written in the same language. Finally, in the frame of the mentioned S2 project, starting from 2008, the program was split into two logical layers: core (CRISIS Core Library) and presentation (CRISIS2008). In addition, a new presentation layer was developed for accessing the same functionalities via Web (CRISISWeb). It is worth noting that CRISIS has been mainly written by people that are, at the same time, PSHA practitioners. Therefore, the development loop has been relatively short, and most of the modifications and improvements have been made to satisfy the needs of the developers themselves.
    Description: Italian Presidenza del Consiglio dei Ministri, Dipartimento della Protezione Civile (DPC).
    Description: Published
    Description: 495-504
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: restricted
    Keywords: Seismic Hazard ; Seismology ; Probabilistic Seismic Hazard Assesment ; PSHA ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
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  • 31
    facet.materialart.
    Unknown
    Seismological Society of America
    Publication Date: 2017-04-03
    Description: An extension of probabilistic seismic hazard analysis is proposed to introduce a priori information about seismic source parameters. In particular, faulting style is taken into account with a theoretical corrective coefficient applied to the attenuation law. The validity of this correction is assessed through a comparison with observed data, attenuation law predictions corrected and not corrected, and the results of attenuation laws containing faulting style parameters. The probabilistic nature of the analysis is maintained, introducing into the classical hazard formulation a 2D probability density function describing the most probable focal mechanisms associated with each seismic source zone. This new expression may also be used in the framework of deaggregation analysis. Thus, the design earthquake resulting from the deaggregation is characterized by a focal mechanism. An application to a site located in the Southern Apennines, Italy, is shown. The result of the analysis emphasizes the importance of strike-slip events in the seismic hazard context, compared with normal faulting seismic activity in this region.
    Description: Published
    Description: 2124-2136
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: restricted
    Keywords: Seismic hazard; Focal mechanism; Ground motion predictive equations ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2017-04-04
    Description: We consider the general problem of constructing or selecting the “best” earthquake forecast/prediction model. While many researchers have presented technical methods for solving this problem, the practical and philosophical dimensions are scarcely treated in the scientific literature, and we wish to emphasize these aspects here. Of particular interest are the marked differ- ences between approaches used to build long-term earthquake rupture forecasts and those used to conduct systematic earth- quake predictability experiments. Our aim is to clarify the dif- ferent approaches, and we suggest that these differences, while perhaps not intuitive, are understandable and appropriate for their specific goals. We note that what constitutes the “best” model is not uniquely defined, and the definition often depends on the needs and goals of the model’s consumer.
    Description: Published
    Description: 442-448
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: model selection ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
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  • 33
    facet.materialart.
    Unknown
    Seismological Society of America
    Publication Date: 2017-04-03
    Description: The single-body mass-spring analog model has been largely used to simulate the recurrence of earthquakes on faults described by rate- and state-dependent rheology. In this paper, the fault was assumed to be governed by the classical slip-weakening (SW) law in which the frictional resistance linearly decreases as the developed slip increases. First, a closed-form fully analytical solution to the 1D elastodynamic problem was derived, expressing the time evolution of the slip and its time derivative. Second, a suitable mechanism for the recovery of stress during the interseismic stage of the rupture was proposed, and this stress recovery was shown quantitatively to make possible the simulation of repeated instabilities with the SW law. Moreover, the theoretical predictions were shown to be compatible with the numerical solutions obtained by adopting a rate and state constitutive model. The analytical solution developed here is, by definition, dynamically consistent and nonsingular. Moreover, the slip velocity function within the coseismic time window found here can be easily incorporated into slip inversion algorithms.
    Description: Published
    Description: 812-821
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: restricted
    Keywords: Earthquake recourrence ; Source time function ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 34
    Publication Date: 2017-04-04
    Description: The growing installation of industrial facilities for subsurface exploration worldwide requires continuous refinements in understanding both the mechanisms by which seismicity is induced by field operations and the related seismic hazard. Particularly in proximity of densely populated areas, induced low-to-moderate magnitude seismicity characterized by high-frequency content can be clearly felt by the surrounding inhabitants and, in some cases, may produce damage. In this respect we propose a technique for time-dependent probabilistic seismic-hazard analysis to be used in geothermal fields as a monitoring tool for the effects of on-going field operations. The technique integrates the observed features of the seismicity induced by fluid injection and extraction with a local ground-motion prediction equation. The result of the analysis is the time-evolving probability of exceedance of peak ground acceleration (PGA), which can be compared with selected critical values to manage field operations. To evaluate the reliability of the proposed technique, we applied it to data collected in The Geysers geothermal field in northern California between 1 September 2007 and 15 November 2010. We show that the period considered the seismic hazard at The Geysers was variable in time and space, which is a consequence of the field operations and the variation of both seismicity rate and b-value.We conclude that, for the exposure period taken into account (i.e., two months), as a conservative limit, PGA values corresponding to the lowest probability of exceedance (e.g., 30%) must not be exceeded to ensure safe field operations. We suggest testing the proposed technique at other geothermal areas or in regions where seismicity is induced, for example, by hydrocarbon exploitation or carbon dioxide storage.
    Description: Published
    Description: 2563–2573
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: restricted
    Keywords: Seismic hazard ; Induced seismicity ; Non-homogeneous poisson model ; The Gysers geothermal area ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    Publication Date: 2017-04-04
    Description: This paper describes the probabilistic assessment of seismic hazard (PSHA) of Italy in view of the building codes from 2003 to 2009. A code was issued in 2003 as Prime Minister Ordinance, requiring that a PSHA for updating the seismic zoning would be performed in one year, in terms of horizontal peak ground acceleration (PGA) with 10% probability of exceedance in 50 years, on hard ground. For the first time in Italy a working group, established by Istituto Nazionale di Geofisica e Vulcanologia (INGV), adopted a logic-tree approach to model the epistemic uncertainty in: the completeness of the earthquake catalog, the assessment of the seismicity rates and Mmax, and the ground motion prediction equations. The seismic hazard has been computed over a grid of more than 16,000 points for the median value (50th percentile), 84th and 16th percentiles of the 16 branches of the logic tree. Using the same input model, PGA values and spectral accelerations for 10 spectral periods were computed for 9 different probabilities of exceedance in 50 years. This wealth of data made it possible to base the design spectra of a new building code on point hazard data instead of being related to just four zones. The 2009, Mw 6.3 L’Aquila earthquake has led many to attempt to test the reliability of this study. In this paper we analyze suggestions coming from that event and conclude that significant changes to the design spectra are not be recommended based just on evidence from the L’Aquila earthquake.
    Description: Published
    Description: 1885–1911
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: restricted
    Keywords: seismic hazard ; italy ; building code ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    Publication Date: 2022-05-26
    Description: © The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The ISME Journal 6 (2012): 1901-1915, doi:10.1038/ismej.2012.31.
    Description: Antarctic surface oceans are well-studied during summer when irradiance levels are high, sea ice is melting and primary productivity is at a maximum. Coincident with this timing, the bacterioplankton respond with significant increases in secondary productivity. Little is known about bacterioplankton in winter when darkness and sea-ice cover inhibit photoautotrophic primary production. We report here an environmental genomic and small subunit ribosomal RNA (SSU rRNA) analysis of winter and summer Antarctic Peninsula coastal seawater bacterioplankton. Intense inter-seasonal differences were reflected through shifts in community composition and functional capacities encoded in winter and summer environmental genomes with significantly higher phylogenetic and functional diversity in winter. In general, inferred metabolisms of summer bacterioplankton were characterized by chemoheterotrophy, photoheterotrophy and aerobic anoxygenic photosynthesis while the winter community included the capacity for bacterial and archaeal chemolithoautotrophy. Chemolithoautotrophic pathways were dominant in winter and were similar to those recently reported in global ‘dark ocean’ mesopelagic waters. If chemolithoautotrophy is widespread in the Southern Ocean in winter, this process may be a previously unaccounted carbon sink and may help account for the unexplained anomalies in surface inorganic nitrogen content.
    Description: CSR was supported by an NSF Postdoctoral Fellowship in Biological Informatics (DBI-0532893). The research was supported by National Science Foundation awards: ANT 0632389 (to AEM and JJG), and ANT 0632278 and 0217282 (to HWD), all from the Antarctic Organisms and Ecosystems Program.
    Keywords: Antarctic bacterioplankton ; Metagenomics ; Chemolithoautotrophy
    Repository Name: Woods Hole Open Access Server
    Type: Article
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    Format: application/pdf
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  • 37
    facet.materialart.
    Unknown
    Seismological Society of America
    Publication Date: 2017-04-04
    Description: 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.
    Description: USGS Senior Scientist In Residence
    Description: Published
    Description: 519-525
    Description: 3.2. Tettonica attiva
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: open
    Keywords: 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)
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  • 38
    Publication Date: 2021-06-21
    Description: Probabilistic seismic hazard analysis is currently the soundest basis for the rational evaluation of ground-motion hazard for site-specific engineering design and assessment purposes. An increasing number of building codes worldwide acknowledge the uniform hazard spectra as the reference to determine design actions on structures and to select input ground motions for seismic structural analysis. This is the case, for example, in Italy where the new seismic code also requires the seismic input for nonlinear dynamic analysis to be selected on the basis of dominating events, for example, identified via disaggregation of seismic hazard. In the present study, the design earthquakes expressed in terms of representative magnitude (M), distance (R), and ε were investigated for a wide region in the southern Apennines, Italy. To this aim, the hazards corresponding to peak ground acceleration and spectral acceleration at 1 sec with a return period of 475 yr were disaggregated. For each of the disaggregation variables the shape of the joint and marginal probability density functions were studied. The first two modes expressed by M, R, and ε were extracted and mapped for the study area. The results shown provide additional information, in terms of source and ground-motion parameters, to be used along with the standard hazard maps to better select the design earthquakes. The analyses also allow us to assess how various frequency ranges of the design spectrum are differently contributed by seismic sources in the study area.
    Description: Published
    Description: 2979–2991
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: seismic hazard ; disaggregation ; Southern Apenniens ; design earthquake ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
    facet.materialart.
    Unknown
    Seismological Society of America
    Publication Date: 2017-04-04
    Description: The evaluation of seismic hazard over wide territories is a basic tool for planning activities aimed at earthquake damage mitigation. This is commonly performed through probabilistic approaches based on the statistical analysis of past seismicity. Among these, due to its wide application worldwide, the Cornell-McGuire approach (Cornell 1968; McGuire 1978) has become a kind of “standard” methodology for probabilistic seismic hazard assessment (PSHA). In Italy, several national seismic hazard maps were produced in recent years (Slejko et al. 1998; Albarello et al. 2000; MPS Working Group 2004) by following this procedure as implemented by Bender and Perkins (1987). Yet despite its widespread application, this standard methodology presents severe drawbacks due to its strong sensitivity to some ill-defined aspects, such as geometry of seismic sources, attenuation of ground motion with distance from the source, completeness of available seismic catalogs, etc. Moreover, this kind of approach does not allow the full exploitation of a large amount of documentary data available at the site about the seismic effects of past earthquakes (Albarello and Mucciarelli 2003). Another drawback is that the standard approach was developed with the assumption that the seismicity database used to feed the computational model is constituted by instrumental data (magnitude, epicentral locations, etc.). However, in many countries (first and foremost, Italy) the bulk of the seismic database is constituted by macroseismic data, and thus the application of the standard method requires a “forcing” of macroseismic information into a para-instrumental format. But macroseismic information is not isomorphic to instrumental data since intensity values are discrete, ordinal, and range-limited. This implies that, in principle, mathematical formalizations suitable to instrumental information cannot be used to manage macroseismic data (see, e.g., Pasolini et al. 2008a, 2008b). To overcome some of these difficulties and to better exploit available information, probabilistic hazard evaluations based on observed intensity data were performed in Europe (Monachesi et al. 1994; Papoulia and Slejko 1997; Azzaro et al. 1999; Albarello et al. 2002) and Japan (Bozkurt et al. 2007) using alternative numerical procedures. An apparent limitation of these studies is the fact that PSH estimates are provided in terms of intensity, and this conflicts with the fact that ground acceleration still remains the traditional output of PSHA devoted to seismic design. However, a new interest has recently grown around macroseismic intensity. In fact, when damage scenarios and post-earthquake emergency planning are of concern, hazard assessment in terms of intensity as ground-shaking measure may be more suitable than conventional estimates based on instrumental parameters (PGA, etc.). A further possible advantage of these kinds of approaches is that they provide hazard evaluations completely independent from the standard ones and more directly linked to empirical observations (local seismic history). Thus, they could represent a useful benchmark for a direct assessment of reliability of traditional PSH estimates (Mucciarelli et al. 2000, 2006, 2008; Bozkurt et al. 2007). In this paper we present the computer program SASHA (Site Approach to Seismic Hazard Assessment), which implements the intensity-based PSHA procedure originally proposed by Magri et al. (1994) and then improved by Albarello and Mucciarelli (2002). It relies on the analysis of the site seismic history, i.e., the dataset of seismic effects (macroseismic intensities) documented during past earthquakes at a given locality. This methodology (hereafter, site approach) has been specifically developed to handle macroseismic data, and thus both the peculiar nature of intensity values (discrete, ordinal, range-limited) and relevant uncertainty (ill-defined intensity values, completeness of site seismic history, etc.) are taken into account by a coherent statistical approach that does not require any assumption about earthquake recurrence model and seismic source geometry. Furthermore, no aftershock removal is required in advance and epicentral data are only considered to integrate (when necessary) felt data at the site. Several PSHA studies have been performed in the last decade in Italy using different versions of the site approach (Mucciarelli et al. 2000; Albarello et al. 2002; D’Amico and Albarello 2003; Albarello, Azzaro et al. 2007; Azzaro et al. 2008). SASHA’s theoretical background is briefly outlined in the next section of the paper. Then, we describe the most important features of SASHA along with a sample application to the Italian area.
    Description: Published
    Description: 663-671
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: JCR Journal
    Description: reserved
    Keywords: computational code ; probabilistic seismic hazard assessment ; intensity data ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 40
    facet.materialart.
    Unknown
    Seismological Society of America
    Publication Date: 2017-04-04
    Description: In 2004, on behalf of the Department of Civil Protection (DPC—Dipartimento della Protezione Civile), the Istituto Nazionale di Geofisica e Vulcanologia (INGV) released a new Italian seismic hazard map. The entire scientific process was public and transparent: an international panel of experts conducted a peer review while the work was in progress, and all the input data, the final output, and the technical documentation was published. The details of the entire process are available on a dedicated Web site (http://zonesismiche.mi.ingv.it). Following the publication of the reference map, the DPC financed the S1 project to produce a set of additional elaborations that would better describe the Italian seismic hazard. This resulted in a set of maps expressed in terms of PGA and Sa (spectral accelerations), both evaluated for different probabilities of exceedance. Finally, the overall information, more than a “set of maps,” can be considered the realization of what can be defined as a complete seismic hazard model. One of the aims of the S1 project is the dissemination of the data through the Web (http://esse1.mi.ingv.it). To evaluate the state of the art in disseminating this type of data we conducted an overview of the Web sites of earthquake-prone countries,and in several cases we experienced difficulties and slowness in finding seismic hazard information for a specific area. Our goal was to provide a tool with a combined high level of interactivity and ease of use. Recognizing the need for a Web application that would enable users to intuitively and interactively locate the area of interest and show pertinent data in various formats, we decided to develop a dedicated Web interface.
    Description: Published
    Description: 68-78
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: 5.4. TTC - Sistema Informativo Territoriale
    Description: 5.9. TTC - Sistema web
    Description: JCR Journal
    Description: reserved
    Keywords: WebGIS ; italy ; seismic hazard ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
    Publication Date: 2017-04-04
    Description: Macroseismic intensity has recently attracted attention as a tool for validating probabilistic seismic hazard assessment (PSHA) studies or as an alternative method for PSHA in countries where the historical catalog is much longer than the instrumental one. In Italy, the new seismic hazard map was recently produced using the Cornell–McGuire approach in terms of the peak ground acceleration characterized by a 10% exceedance probability for an exposure time of 50 yr (Amax). We compare this map with an alternative one, produced using a different approach based on a nonparametric and zonation-free statistical analysis of local seismic histories. In this case, results are expressed in terms of the maximum intensity corresponding to an exceedance probability of not less than 10% for an exposure time of 50 yr (Iref ). In order to compare the two maps, we selected 1401 control sites, where local seismic history includes at least 10 intensity values relative to felt effects documented during past earthquakes. The values of Amax and Iref at these sites have been ranked in the respective domains. The spatial distribution of rank differences of Amax and Iref values shows a strong correlation with the seismogenic zoning used in the calculation of PSHA following the Cornell–McGuire approach. This suggests that the adopted zoning could be incomplete (some further “hidden” sources may exist) and too rough to capture actual seismogenic sources. Because more detailed zoning is prevented by the amount of data available, the results obtained suggest the preference of zonation-free approaches for seismic hazard assessment in Italy. Furthermore, among the possible zonation-free approaches, those that offer better exploitation of local information about the effects of past earthquakes would be preferred.
    Description: Published
    Description: 2652–2664
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: JCR Journal
    Description: reserved
    Keywords: probabilistic seismic hazard estimates ; statistical analysis ; Italy ; 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)
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  • 42
    facet.materialart.
    Unknown
    Seismological Society of America
    In:  Convertito, V., and A. Herrero (2004). Influence of focal mechanism in probabilistic seismic hazard analysis, Bull. Seism. Soc. Am. 94, no. 6, 2124–2136.
    Publication Date: 2017-04-04
    Description: The influence of style-of-faulting on strong groundmotions has been the subject of debate for some time. Although some controversy persists, the general consensus is that ground motions produced by reverse faults are higher than those produced by normal faults, whereas motions from strike-slip faults are somewhere in between. In a recent article, Convertito and Herrero (2004) derived a correction factor for focal mechanism to be applied to predictive equations. This issue was previously addressed by Bommer et al. (2003). Although this article is cited by Convertito and Herrero, it seems that its aims and scope were not well understood, and we would therefore like to clarify what the method presented therein entails, especially because we feel that Convertito and Herrero’s approach of characterizing focal mechanisms based solely on the radiation pattern is difficult to justify. After presenting their correction scheme, Convertito and Herrero go on to present an implementation of probabilistic seismic hazard analysis (PSHA) explicitly accounting for focal mechanism. This represents a real innovation in terms of methodology because it allows propagation of the improvements in ground-motion prediction gained through the focal-mechanism adjustments to hazard estimation. Characterizing the dominant scenario in terms of focal mechanism furthermore has the advantage of providing constraints for numerical simulations that are derived directly from the hazard computation, rather than from arbitrary assumptions. However, in our opinion, the methodology presented by Convertito and Herrero has some serious shortcomings which would need to be addressed before it can lead to improvements of the PSHA methodology. Our discussion includes a comparison with the new Italian seismic hazard map, which was derived using the Bommer et al. (2003) adjustment methodology.
    Description: Published
    Description: 750-753
    Description: JCR Journal
    Description: reserved
    Keywords: strong ground-motions ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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