Contributors: Bureau d'évaluation des risques sismiques pour la sûreté des installations (IRSN/PSE-ENV/SCAN/BERSSIN); Service de caractérisation des sites et des aléas naturels (IRSN/PSE-ENV/SCAN); Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN); Institut des Sciences de la Terre (ISTerre); Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG)-Université Grenoble Alpes (UGA); EGIS; Bureau de Recherches Géologiques et Minières (BRGM); German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ); Bureau d'expertise en hydrogéologie, risques Inondation, météorologiques et géotechniques (IRSN/PSE-ENV/SCAN/BEHRIG); French National Research Agency (Agence Nationale de la Recherche, ANR, project number ANR-19-CE31-0029); German Research Foundation (Deutsche Forschungsgemeinschaft, DFG, project number 431362334); Institut de Radioprotection et de Sûreté Nucléaire - IRSN; HPC resources of TGCC under the allocation 2022-gen13461 made by GENCI (https://www.genci.fr).; HPC resources of the GRICAD infrastructure (https://gricad.univ-grenoble-alpes.fr).; ANR-19-CE31-0029,DARE,Réseau dense pour l'estimation des effets de site sismiques(2019); ANR-10-LABX-0056,OSUG@2020,Innovative strategies for observing and modelling natural systems(2010)
نبذة مختصرة : This work is part of the DARE project (Dense ARray for site effect Estimation, https://anr.fr/Projet-ANR-19-CE31-0029), funded by the French National Research Agency (Agence Nationale pour la Recherche, ANR, grant number ANR19-CE31-0029) and by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG, project number 431362334). ISTerre is part of Labex OSUG@2020 (ANR10 LABX56).Numerical simulations have been performed with the EFISPEC software developed at BRGM (https://gitlab.brgm.fr/brgm/efispec3d). This work was granted access to the HPC resources of TGCC under the allocation 2022-gen13461 made by GENCI, and of the GRICAD infrastructure (https://gricad.univ-grenoble-alpes.fr), which is supported by Grenoble research communities. ; International audience ; In certain geological settings such as sedimentary basins, the ground motion induced by an earthquake may be amplified by local site conditions. Estimating these site effects is important for seismic hazard assessment but can be difficult to do empirically due to the scarcity of site-specific field data in time and space, especially in low-to-moderate seismicity regions where the earthquakes needed for measuring the site effects have long return periods. In this study, we try to overcome these limitations and investigate an alternative approach based on ambient seismic noise and numerical simulations. More specifically, we use a 3D numerical model of seismic properties derived from Ambient Noise Surface-Wave Tomography (ANSWT) for 3D numerical simulations of seismic wave propagation, and consequently for a numerical estimation of seismic amplification in the basin. We illustrate the approach on a target site located in the French Rhône valley, where the Messinian salinity crisis has dug a paleo-canyon which is now filled by soft sediments in direct contact with a harder substratum, thereby providing typical conditions for significant site effects, as also observed by previous studies in the area. This work makes use of two dedicated datasets. On ...
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