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Sgobba, Sara
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Sgobba, Sara
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Sgobba, Sara Anna
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sara.sgobba@ingv.it
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23493526300
38 results
Now showing 1 - 10 of 38
- PublicationOpen AccessToward a renewed data processing of the Engineering Strong Motion (ESM) database(2023)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Strong-motion records and open access to strong-motion data repositories are fundamental to seismology, earthquake engineering and practice. The main archive to disseminate high quality processed waveforms for the European-Mediterranean region is the Engineering Strong-Motion Database (ESM, https://esm-db.eu). ESM is developed under the general coordination of the ORFEUS Strong-Motion Management Committee (Observatories and Research facilities for European Seismology; http://orfeus-eu.org/), with the aim to provide users daily access to updated strong-motion waveforms of earthquakes with magnitude greater than 4, mainly recorded in the Pan-European regions. ESM is fully compatible with the European Integrated Data Archive (EIDA; http://orfeus-eu.org/data/eida/) and disseminates waveforms and related metadata according to the Federation of Digital Seismograph Networks (FDSN, https://www.fdsn.org/networks/). The strategy of ESM is to disseminate only manually processed data to ensure the highest quality. However, the rapid increase in the number of waveforms, due to the increment of seismic stations, leads to the need of automatic procedures for data processing and data quality control. In this work, we present ESMpro, a modular Python software for a renewed processing framework of ESM. The ESM data processing is improved with: (1) automated data quality-check that speeds up the processing time through the rejection of poor-quality records; (2) advancement of the automatic settings for waveform trimming and filtering; (3) introduction of different algorithms for data processing (Paolucci et al., 2011; Schiappapietra et al., 2021); (4) modular and flexible software structure that allows the addition of new algorithms and custom workflows. The accuracy of the updated automatic processing is evaluated by comparison with the waveforms processed by expert analysts, used as benchmarks (Mascandola et al., 2022). ESMpro is distributed in a stand-alone Beta version available on GitLab (D’Amico et al., 2022; https://shake.mi.ingv.it/esmpro/), following the Open Science principles to promote collaborations and contributions from the scientific community. In the next future, a renewed ESM web-processing frontend will be developed to include the ESMpro improvements, as well as new functionalities to process stand-alone data (i.e., not stored in the ESM database) and to allow different input seismic data formats. How to cite: Mascandola, C., D'Amico, M., Russo, E., Luzi, L., Lanzano, G., Felicetta, C., Pacor, F., and Sgobba, S.: Toward a renewed data processing of the Engineering Strong Motion (ESM) database, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2210, https://doi.org/10.5194/egusphere-egu23-2210, 2023.24 2 - PublicationRestrictedEmpirical nonergodic shaking scenarios based on spatial correlation models: An application to central Italy(2021)
; ; ; ; ; This paper provides a new methodological framework to generate empirical ground shaking scenarios, designed for engineering applications and civil protection planning. The methodology is useful both to reconstruct the ground motion pattern of past events and to generate future shaking scenarios, in regions where strong-motion datasets from multiple events and multiple stations are available. The proposed methodology combines (1) an ad-hoc nonergodic ground motion model (GMM) with (2) a spatial correlation model for the source region-, site-, and path-systematic residual terms, and (3) a model of the remaining aleatory error to take into account for directivity effects. The associated variability is a function of the type of scenario generated (bedrock or site, past or future event) and it is minimal for source areas where several events have occurred and for sites where recordings are available. In order to develop the region-specific fully nonergodic GMM and to compute robust estimation of the residual terms, the approach is calibrated on a highly dense dataset compiled for the area of central Italy. Example tests demonstrate the validity of the approach, which allows to simulate acceleration response spectra at unsampled sites, as well as to capture peculiar physical features of ground motion patterns in the region. The proposed approach could be usefully adopted for data-driven simulations of ground shaking maps, as alternative or complementary tool to physic-based and stochastic-based approaches.531 7 - PublicationEmbargoConstraining Between-Event Variability of Kinematic Rupture Scenarios by Empirical Ground-Motion Model: A Case Study in Central Italy(2024)
; ; ; ; ; ; ;; ; ; ;The region of central Italy is well known for its moderate-to-large earthquakes. Events such as 2016 Mw 6.2 Amatrice, generated in the shallow extensional tectonic regime, motivate numerical simulations to gain insights into source-related ground-motion complexities. We utilize a hybrid integral–composite kinematic rupture model by Gallovič and Brokešová (2007) to predict ground motions for other hypothetical Amatrice fault rupture scenarios (scenario events). The synthetic seismograms are computed in 1D crustal velocity models, including region-specific 1D profiles for selected stations up to 10 Hz. We create more than ten thousand rupture scenarios by varying source parameters. The resulting distributions of synthetic spectral accelerations at periods 0.2–2 s agree with the empirical nonergodic ground-motion model ofSgobbaetal.(2021)forcentral Italy in terms of the mean and total variability. However, statistical mixed-effect analysis of the residuals indicates that the between-eventvariability of the scenarios exceeds theempirical one significantly. We quan tify the role ofsourcemodelparametersinthemodelinganddemonstratethepivotalroleof theso-called stress parameterthatcontrols high-frequencyradiation. Weproposerestricting thescenariovariability tokeepthebetween-eventvariabilitywithintheempiricalvalue.The presented validation of the scenario variability can be generally utilized in scenario model ing for more realistic physics-based seismic hazard assessment.127 21 - PublicationOpen AccessDatabase, web-services, and tools to access and analyze seismic waveforms records: the periodic release of the Italian accelerometric archive(2019-11-14)
; ; ; ; ; ; ; ; ; ; ; ; ; The different versions of ITACA released over the years testify the great effort invested to its development and, in particular, to: 1) populate the database; 2) standardize waveforms and metadata formats according to the Federation of Digital Seismograph Networks (FDSN https://www.fdsn.org/networks/); 3) process the signals by means of standard procedures; 4) create queries for exploring events, stations, and waveforms metadata; 5) access and download accelerometric waveforms and related metadata; 6) select suites of spectrum-compatible ground-motion waveforms; 7) provide seismological products useful for the calibration of ground-motion models. The ITACA target users are researchers and students in the fields of applied seismology and earthquake engineering, professional engineers or geologists and policy makers. The number of users has grown over time, every day ITACA is visited by nearly 250 unique users. A considerable number of scientific papers is directly or indirectly linked to the ITACA services or products (Luzi et al., 2009; Paolucci et al., 2010; Pacor et al., 2011; Bindi et al., 2011; Puglia et al., 2018 among others). The growing interest to the open access to ground-motion data, web-services, and tools motivate every year a new ITACA release. The current one (ITACA 3.0 on March 2019 http://itaca.mi.ingv.it), in particular, has a renewed web interface and substantial changes in the database content and services. In this work, we present a brief overview of the main features of ITACA 3.0132 190 - PublicationRestrictedSpatial Correlation Model of Systematic Site and Path Effects for Ground‐Motion Fields in Northern Italy(2019)
; ; ; ; ; ; ; ; ; ; ; ; ; In this study, we propose an approach to generate spatially correlated seismic ground-motion fields for loss assessment and risk analysis. Differently from the majority of spatial correlation models, usually calibrated on within-earthquake residuals, we use the sum of the source-, site-, and path-systematic effects (namely corrective terms) of the ground-motion model (GMM), obtained relaxing the ergodic assumption. In this way, we build a scenario-related spatial correlation model of the corrective terms by which adjusting the median predictions of ground motion and the associated variability. We show a case study focused on the Po Plain area in northern Italy, presenting a series of peculiar features (i.e., availability of a dense dataset of seismic records with uniform soil classification and very large plain with variable thickness of the sedimentary cover) that make its study particularly suitable for the purpose of developing and validating the proposed approach. The study exploits the repeatable corrective terms, estimated by Lanzano et al. (2017) in northern Italy, using a local GMM (Lanzano et al., 2016), which predicts the geometric mean of horizontal response spectral accelerations in the 0.01–4 s period range. Our results show that the implementation of a spatially correlated model of the systematic terms provides reliable shaking fields at various periods and spatial pat- terns compliant with the deepest geomorphology of the area, which is an aspect not accounted by the GMM model. The possibility to define a priori fields of systematic effects depending on local characteristics could be usefully adopted either to simulate future ground-motion scenarios or to reconstruct past events.1280 5 - PublicationOpen AccessUpdate of the ground motion prediction equations for Italy(2019-06)
; ; ; ; ; ; ; ; ; ; ; ; ; The Ground Motion Prediction Equations (GMPEs) of Bindi et al. (2011) are now- adays considered as the reference predictive equations for shallow crustal events in Italy. How- ever, the maximum usable magnitude for the hazard assessment is 6.9 and the longest periods (>1s) are not well constrained. In this paper, we discuss a new set of GMPEs for Italy: the general philosophy is to achieve the accuracy of the prediction maintaining the simplicity of the functional form used by Bindi et al (2011). We build up a dataset of Italian waveforms, adding 12 worldwide events with magnitude range 6.1 - 8.0. The dataset encompasses about 5,000 waveforms, resulting in a number of records which is about five times larger than those used by Bindi et al. (2011). The GMPEs are derived for the horizontal component of PGA, PGV and 36 ordinates of acceleration response spectra (5% damping) in the period range 0.01–10s.130 251 - PublicationOpen AccessSPATIAL CORRELATION OF THE SYSTEMATIC SITE- AND PATHSPECIFIC CORRECTIONS OF A GMPE CALIBRATED IN NORTHERN ITALY(2018-06-18)
; ; ; ; ; ; ; ; ; ; ; ; ; The probabilistic assessment of the seismic hazard (PSHA) at an individual site is a standard practice, but an ergodic assumption is commonly made: the ground-motion uncertainty computed by a Ground Motion Prediction Equation (GMPE) from a global dataset is assumed to be the same as the variability at a single site. In this paper, the ergodic assumption is relaxed by means of a residual analysis, accounting for the impacts on both the median and aleatory standard deviation of a GMPE. The aleatory variability is separated from the systematic source, path and site effects using a strong motion data set from Northern Italy with multiple recordings at each site and multiple earthquakes within small regions. A local model, specifically tailored for the area, is used as the reference GMPE, which predicts the geometric mean of horizontal response spectral accelerations in the period range 0.04-4s. The spatial covariance of such repeatable effects is modeled, in order to generate spatially correlated fields of path, source and site corrections and their associated variabilities. The results can be used to prepare fully non-ergodic hazard maps of parameters of engineering interest.233 224 - PublicationOpen AccessAssessing the impact of an updated spatial correlation model of ground motion parameters on the italian shakemap(2023)
; ; ; ; ; ; ; This study develops a new spatial correlation model for Italy using the most up-to-date and densest dataset of accelerometer and velocimeter records available. The objective is to estimate the average correlation length and assess its impact on the prediction accuracy of the Italian Shakemap compared to the global model (Loth and Baker, 2013–LB13) adopted in the default configuration of the program. We compute the spatial covariance structure using a geostatistical approach based on traditional variography applied to standardized residuals within the events of a reference ground motion model (ITA10). We observe spatial clusters of the correlation lengths and a wide variability over the Italian territory linked to the profound heterogeneity of the geological and geomorphological context. The obtained estimates are then implemented within the LB13 co-regionalization model in place of the default values while assuming the same cross-correlation coefficients among spectral parameters. Although our results are quite consistent with previous models calibrated for Italy, we find that the inclusion of the new correlation lengths in the Shakemap predictions, assessed through a leave-one-out cross-validation technique, results in a non-appreciable improvement over the global model, thus indicating that the adopted approach is not able to resolve the regional features and the corresponding spatial correlation with reference to individual scenarios. These findings may suggest the need to move towards nonergodic models in the Shakemap computing to better capture the spatial variability or to determine different co-regionalisation matrices more suitable for the regional applications.283 15 - PublicationOpen AccessThe pan-European Engineering Strong Motion (ESM) flatfile: comparison with NGA-West2 database(2020)
; ; ; ; ; ; ; ; ; ; ; ; ; In the first months of 2018, a parametric table (flatfile) related to the Engineering Strong Motion (ESM) database was released and disseminated through a website (http:// esm.mi.ingv.it/flatfile-2018). The flatfile contains intensity measures of engineering interest and associated metadata of three-components manually processed waveforms. The uniform collection of strong motion data and the compiling of quality-checked metadata allow the users among practitioners and seismologists, to test and calibrate Ground Motion Models (GMMs) for hazard assessment purposes or for the analysis of the seismic structural response. In 2013, a database used for similar purposes was constructed in the framework of the NGA-West2 project, whose main objective is to update and improve the Next Generation Attenuation (NGA) models for active tectonic regions, such as California. In this framework, a flatfile containing several parameters, such as peak parameters and ordinates of the pseudo-acceleration elastic response spectra, along with metadata of events and stations was released. The scope of this paper is to highlight the main differences between the two tables in terms of structure, data statistics and qualification of metadata.1550 215 - PublicationOpen AccessA site-specific earthquake ground response analysis using a fault-based approach and nonlinear modeling: the Case Pente site (Sulmona, Italy)(2023-02)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; In this paper we present the ground response analyses (GRA) of a site where an industrial facility is planned. Because of its location on an active normal fault system known as a relevant seismic gap, the Mt. Morrone Fault system (MMF), and at the edge of a basin filled with slow velocity continental deposits, a inter-disciplinary and non-standard approach has been applied to assess the seismic input of the dynamic numerical analyses. It includes geological, seismological, geotechnical and engineering contributions. Two fault scenarios, MMF1 and MMF2, were considered and scenario-based (SSHA) and probabilistic (time-dependent, TD, and time-independent, TI) seismic hazard (PSHA) analyses were implemented. Comparison among the spectra corresponding to the 90th percentile of the SSHA statistical distribution and the PSHA average ones, shows that the MMF2 has values similar to the TD model. The SSHA 90th percentile distribution was selected as target spectra to retrieve the seismic input for GRA. Nonlinear numerical simulations of seismic wave propagation were implemented to derive surface ground motion parameters. GRA acceleration response spectra and their PGA are notably higher, and thus on the safety site, than those obtained following the Italian code approach for seismic resistant buildings. These results confirm that a scenario-based methodology can better capture the shaking effect in near-field conditions, avoiding possibly unconservative underestimations of the seismic actions and in view of a more robust performance-based approach used by engineers for either new design and/or assessment/retrofit purposes of the built environment.651 32