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  • 1
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    A preliminary evaluation of the tsunamigenic potential of the active faults at the Alboran Basin (westernmost Mediterranean) based on new seismic data (2019)
    In:  [Poster] In: EGU General Assembly 2019, 07.-12.04.2019, Vienna, Austria .
    Details
    Publication Date: 2020-01-10
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
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    OceanRep: Poster
  • 2
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    Evaluation of the tsunamigenic potential of the largest active faults in the Alboran Basin (westernmost Mediterranean Sea) (2019)
    In:  [Poster] In: AGU Fall Meeting 2019, 09.-13.12.2019, San Francisco, USA .
    Details
    Publication Date: 2020-01-10
    Type: Conference or Workshop Item , NonPeerReviewed
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    OceanRep: Poster
  • 3
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    Sensitivity of Tsunami Scenarios to Complex Fault Geometry and Heterogeneous Slip Distribution: Case‐Studies for SW Iberia and NW Morocco (2021)
    AGU (American Geophysical Union) | Wiley
    Details
    Publication Date: 2024-02-07
    Description: The SW Iberian margin is one of the most seismogenic and tsunamigenic areas in W-Europe, where large historical and instrumental destructive events occurred. To evaluate the sensitivity of the tsunami impact on the coast of SW Iberia and NW Morocco to the fault geometry and slip distribution for local earthquakes, we carried out a set of tsunami simulations considering some of the main known active crustal faults in the region: the Gorringe Bank (GBF), Marquês de Pombal (MPF), Horseshoe (HF), North Coral Patch (NCPF) and South Coral Patch (SCPF) thrust faults, and the Lineament South (LSF) strike-slip fault. We started by considering for all of them relatively simple planar faults featuring with uniform slip distribution; we then used a more complex 3D fault geometry for the faults constrained with a large 2D multichannel seismic dataset (MPF, HF, NCPF, and SCPF); and finally, we used various heterogeneous slip distributions for the HF. Our results show that using more complex 3D fault geometries and slip distributions, the peak wave height at the coastline can double compared to simpler tsunami source scenarios from planar fault geometries. Existing tsunami hazard models in the region use homogeneous slip distributions on planar faults as initial conditions for tsunami simulations and therefore underestimate tsunami hazard. Complex 3D fault geometries and non-uniform slip distribution should be considered in future tsunami hazard updates. The tsunami simulations also support the finding that submarine canyons attenuate the wave height reaching the coastline, while submarine ridges and shallow shelves have the opposite effect.
    Type: Article , PeerReviewed
    Format: text
    Format: other
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Quantification of source uncertainties in Seismic Probabilistic Tsunami Hazard Analysis (SPTHA) (2016)
    Oxford University Press
    Details
    Publication Date: 2016-05-05
    Description: We propose a procedure for uncertainty quantification in Probabilistic Tsunami Hazard Analysis (PTHA), with a special emphasis on the uncertainty related to statistical modelling of the earthquake source in Seismic PTHA (SPTHA), and on the separate treatment of subduction and crustal earthquakes (treated as background seismicity). An event tree approach and ensemble modelling are used in spite of more classical approaches, such as the hazard integral and the logic tree. This procedure consists of four steps: (1) exploration of aleatory uncertainty through an event tree, with alternative implementations for exploring epistemic uncertainty; (2) numerical computation of tsunami generation and propagation up to a given offshore isobath; (3) (optional) site-specific quantification of inundation; (4) simultaneous quantification of aleatory and epistemic uncertainty through ensemble modelling. The proposed procedure is general and independent of the kind of tsunami source considered; however, we implement step 1, the event tree, specifically for SPTHA, focusing on seismic source uncertainty. To exemplify the procedure, we develop a case study considering seismic sources in the Ionian Sea (central-eastern Mediterranean Sea), using the coasts of Southern Italy as a target zone. The results show that an efficient and complete quantification of all the uncertainties is feasible even when treating a large number of potential sources and a large set of alternative model formulations. We also find that (i) treating separately subduction and background (crustal) earthquakes allows for optimal use of available information and for avoiding significant biases; (ii) both subduction interface and crustal faults contribute to the SPTHA, with different proportions that depend on source-target position and tsunami intensity; (iii) the proposed framework allows sensitivity and deaggregation analyses, demonstrating the applicability of the method for operational assessments.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 5
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    A smoothed stochastic earthquake rate model considering seismicity and fault moment release for Europe (2014)
    Oxford University Press
    Details
    Publication Date: 2014-06-30
    Description: We present a time-independent gridded earthquake rate forecast for the European region including Turkey. The spatial component of our model is based on kernel density estimation techniques, which we applied to both past earthquake locations and fault moment release on mapped crustal faults and subduction zone interfaces with assigned slip rates. Our forecast relies on the assumption that the locations of past seismicity is a good guide to future seismicity, and that future large-magnitude events occur more likely in the vicinity of known faults. We show that the optimal weighted sum of the corresponding two spatial densities depends on the magnitude range considered. The kernel bandwidths and density weighting function are optimized using retrospective likelihood-based forecast experiments. We computed earthquake activity rates ( a - and b -value) of the truncated Gutenberg–Richter distribution separately for crustal and subduction seismicity based on a maximum likelihood approach that considers the spatial and temporal completeness history of the catalogue. The final annual rate of our forecast is purely driven by the maximum likelihood fit of activity rates to the catalogue data, whereas its spatial component incorporates contributions from both earthquake and fault moment-rate densities. Our model constitutes one branch of the earthquake source model logic tree of the 2013 European seismic hazard model released by the EU-FP7 project ‘Seismic HAzard haRmonization in Europe’ (SHARE) and contributes to the assessment of epistemic uncertainties in earthquake activity rates. We performed retrospective and pseudo-prospective likelihood consistency tests to underline the reliability of our model and SHARE's area source model (ASM) using the testing algorithms applied in the collaboratory for the study of earthquake predictability (CSEP). We comparatively tested our model's forecasting skill against the ASM and find a statistically significant better performance for testing periods of 10–20 yr. The testing results suggest that our model is a viable candidate model to serve for long-term forecasting on timescales of years to decades for the European region.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 6
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    A smoothed stochastic earthquake rate model considering seismicity and fault moment release for Europe (2014)
    Oxford University Press
    Details
    Publication Date: 2014-07-03
    Description: We present a time-independent gridded earthquake rate forecast for the European region including Turkey. The spatial component of our model is based on kernel density estimation techniques, which we applied to both past earthquake locations and fault moment release on mapped crustal faults and subduction zone interfaces with assigned slip rates. Our forecast relies on the assumption that the locations of past seismicity is a good guide to future seismicity, and that future large-magnitude events occur more likely in the vicinity of known faults. We show that the optimal weighted sum of the corresponding two spatial densities depends on the magnitude range considered. The kernel bandwidths and density weighting function are optimized using retrospective likelihood-based forecast experiments. We computed earthquake activity rates ( a - and b -value) of the truncated Gutenberg–Richter distribution separately for crustal and subduction seismicity based on a maximum likelihood approach that considers the spatial and temporal completeness history of the catalogue. The final annual rate of our forecast is purely driven by the maximum likelihood fit of activity rates to the catalogue data, whereas its spatial component incorporates contributions from both earthquake and fault moment-rate densities. Our model constitutes one branch of the earthquake source model logic tree of the 2013 European seismic hazard model released by the EU-FP7 project ‘Seismic HAzard haRmonization in Europe’ (SHARE) and contributes to the assessment of epistemic uncertainties in earthquake activity rates. We performed retrospective and pseudo-prospective likelihood consistency tests to underline the reliability of our model and SHARE's area source model (ASM) using the testing algorithms applied in the collaboratory for the study of earthquake predictability (CSEP). We comparatively tested our model's forecasting skill against the ASM and find a statistically significant better performance for testing periods of 10–20 yr. The testing results suggest that our model is a viable candidate model to serve for long-term forecasting on timescales of years to decades for the European region.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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    PAPER CURRENT
  • 7
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    Ground-Motion Variability for Single Site and Single Source through Deterministic Stochastic Method Simulations: Implications for PSHA (2017)
    Seismological Society of America (SSA)
    Details
    Publication Date: 2017-03-23
    Description: The ground-motion median and standard deviation of empirical ground-motion prediction equations (GMPEs) are usually poorly constrained in the near-source region due to the general lack of strong-motion records. Here we explore the use of a deterministic–stochastic simulation technique, specifically tailored to reproduce directivity effects, to evaluate the expected ground motion and its variability at a near-source site, and seek a strategy to overcome the known GMPEs limitations. To this end, we simulated a large number of equally likely scenario events for three earthquake magnitudes ( M w  7.0, 6.0, and 5.0) and various source-to-site distances. The variability of the explored synthetic ground motion is heteroscedastic, with smaller values for larger earthquakes. The standard deviation is comparable with empirical estimates for smaller events and reduces by 30%–40% for stronger earthquakes. We then illustrate how to incorporate directivity effects into probabilistic seismic-hazard analysis (PSHA). This goal is pursued by calibrating a set of synthetic GMPEs and reducing their aleatory variability (~50%) by including a predictive directivity term that depends on the apparent stress parameter obtained through the simulation method. Our results show that, for specific source-to-site configurations, the nonergodic PSHA is very sensitive to the additional epistemic uncertainty that may augment the exceedance probabilities when directivity effects are maximized. The proposed approach may represent a suitable way to compute more accurate hazard estimates. Electronic Supplement: Histograms of synthetic peak ground accelerations (PGAs) and peak ground velocities (PGVs).
    Print ISSN: 0037-1106
    Electronic ISSN: 1943-3573
    Topics: Geosciences , Physics
    Published by Seismological Society of America (SSA)
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  • 8
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    Stress releasemodel and proxy measures of earthquake size. Application to Italian seismogenic sources (2016)
    Elsevier Science Limited
    Details
    Publication Date: 2021-05-12
    Description: This study presents a series of self-correcting models that are obtained by integrating information about seismicity and fault sources in Italy. Four versions of the stress release model are analyzed, in which the evolution of the system over time is represented by the level of strain, moment, seismic energy, or energy scaled by the moment. We carry out the analysis on a regional basis by subdividing the study area into eight tectonically coherent regions. In each region, we reconstruct the seismic history and statistically evaluate the completeness of the resulting seismic catalog. Following the Bayesian paradigm, we apply Markov chain Monte Carlo methods to obtain parameter estimates and a measure of their uncertainty expressed by the simulated posterior distribution. The comparison of the four models through the Bayes factor and an information criterion provides evidence (to different degrees depending on the region) in favor of the stress release model based on the energy and the scaled energy. Therefore, among the quantities considered, this turns out to be the measure of the size of an earthquake to use in stress release models. At any instant, the time to the next event turns out to follow a Gompertz distribution, with a shape parameter that depends on time through the value of the conditional intensity at that instant. In light of this result, the issue of forecasting is tackled through both retrospective and prospective approaches. Retrospectively, the forecasting procedure is carried out on the occurrence times of the events recorded in each region, to determine whether the stress release model reproduces the observations used in the estimation procedure. Prospectively, the estimates of the time to the next event are compared with the dates of the earthquakes that occurred after the end of the learning catalog, in the 2003–2012 decade.
    Description: Italian Dipartimento della Protezione Civile in the framework of the 2007–2009 Agreement with Istituto Nazionale di Geofisica e Vulcanologia (INGV), project S1: Analysis of the seismic potential in Italy for the evaluation of the seismic hazard.
    Description: Published
    Description: 147-168
    Description: 2T. Tettonica attiva
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: point process ; probabilistic forecasting ; interevent time distribution ; seismogenic sources ; Bayesian inference ; 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::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 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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  • 9
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    Earthquake-induced tsunamis in the Mediterranean Sea: scenarios of potential threats to southern Italy (2006)
    Details
    Publication Date: 2020-10-22
    Description: The huge loss of lives and the destruction caused by the 2004 Indian Ocean tsunami dramatically showed the need for a reassessment of tsunami hazard and risk in coastal regions prone to this threat. It is known that many countries facing the Mediterranean basin have been affected by several tsunamis in the past, some of which were catastrophic over large areas. Our work aims to quantitatively address the problem of the tsunami hazard and risk assessment by means of numerical simulation of earthquake-induced tsunami scenarios. The work is part of a larger project, funded by the Italian Department for Civil Defense, whose main goal is the evaluation of the seismogenic potential and of the probability of occurrence of strong earthquakes in Italy. Here we show some preliminary results concerning the analysis of several simulated tsunami scenarios. On the basis of tsunami catalogues and seismogenic source databases, we selected a set of tectonic sources that, owing to their location and/or size, are believed to be especially hazardous for the Italian coasts. Once the geometrical parameters of the fault are defined (on the basis of geological and seismological evidence and constraints), we compute the coseismic vertical displacement of the seafloor, which represents the initial condition of the tsunami propagation problem. Then we solve the propagation equations (the wide used shallow-water equations) through a finite difference technique. The main outputs of a single run are the wavefields at desired times, useful to estimate the arrival times of the wavefronts, and the maximum water elevation field that gives at-glance information on the tsunami energy focusing during the whole propagation. Furthermore, for those stretches of coast that are particularly vulnerable (owing to high population density, presence of important infrastructures, etc.) we make a more detailed analysis of the wave impact. Among the tectonic sources we studied, the 365 AD Crete earthquake indeed represents a serious threat for the Italian coastlines facing the Ionian Sea, where we estimated a wave height exceeding 1-2 meters along hundreds of km of the coast. Furthermore, the first wavefront from this source is expected to reach the coasts of southern Italy in less than 1 hour from the origin time of the parent earthquake. This finding stresses the need for an especially early warning by the geophysical monitoring systems and by the Civil Defense structures.
    Description: Convenzione INGV - DPC 2004-2006 Progetti Sismologici e Vulcanologici di interesse per il Dipartimento della Protezione Civile Progetto S2 - Valutazione del potenziale sismogenetico e probabilità dei forti terremoti in Italia
    Description: Published
    Description: Vienna, Austria
    Description: open
    Keywords: Tsunami hazard ; Risk assessment ; Seismogenic source ; Mediterranean Sea ; Southern Italy ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
    Format: 3346130 bytes
    Format: application/pdf
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  • 10
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    Monitoraggio in area sismica di beni monumentali: tecniche NDT e procedure di verifica (2014)
    AIPnD - Associazione Italiana Prove non Distruttive
    Details
    Publication Date: 2020-12-15
    Description: Negli ultimi anni il concetto di vulnerabilità sismica è tristemente entrato a far parte delle conoscenze anche dei non addetti ai lavori. Infatti, gli eventi sismici che hanno interessato dagli inizi del ‘900 il territorio Italiano, hanno sistematicamente messo in risalto l’elevata vulnerabilità sismica del nostro patrimonio edilizio, ivi compresi i beni monumentali, nonché, l’inesistenza di qualsiasi attività di programmazione della manutenzione periodica ordinaria e straordinaria delle strutture sismo-resistenti, che garantiscono nel tempo la conservazione delle loro capacità di risposta alle perturbazioni esterne.Il progetto PON sul Monitoraggio in Area Sismica di SIstemi MOnumentali nasce con la prerogativa di produrre uno strumento dedicato alla tutela di strutture a valenza storico – artistica, attraverso un percorso di catalogazione, di analisi del bene inteso come elemento costituito da elementi resistenti e da materiali, di studio del sito dove la struttura è ubicata e di attività di monitoraggio.
    Description: PON 01/02710 MASSIMO - Monitoraggio in Area SiSmica di benI MOnumentali
    Description: Published
    Description: 41-51
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: 5T. Sorveglianza sismica e operatività post-terremoto
    Description: N/A or not JCR
    Description: open
    Keywords: beni monumentali ; tecniche NDT ; monitoraggio ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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