Impacts of geometric model simplifications on wave propagation—application to ground motion simulation in the lower Var valley basin (France)
| Autor: | Pierre Anquez, Guillaume Caumon, Paul Cupillard, Nathalie Glinsky |
|---|---|
| Přispěvatelé: | GeoRessources, Institut national des sciences de l'Univers (INSU - CNRS)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Centre d'études et d'expertise sur les risques, l'environnement, la mobilité et l'aménagement - Equipe-projet Repsody (Equipe-projet Repsody), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Ecole Nationale Supérieure de Géologie (ENSG), Université de Lorraine (UL), RING-GOCAD Consortium, RING - Research for Integrative Numerical Geology |
| Rok vydání: | 2021 |
| Předmět: |
Ground motion
Wave propagation Site effects [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Geometry Earthquake hazards Structural basin Physics::Geophysics Computational seismology Geophysics Numerical modelling [SDU]Sciences of the Universe [physics] Geochemistry and Petrology Geometric modeling Geology Compositionand structure of the continental crust |
| Zdroj: | Geophysical Journal International Geophysical Journal International, 2022, 229 (1), pp.110-137. ⟨10.1093/gji/ggab447⟩ |
| ISSN: | 1365-246X 0956-540X |
| DOI: | 10.1093/gji/ggab447 |
| Popis: | SUMMARYThe numerical simulation of seismic wave propagation in realistic heterogeneous media, as sedimentary basins, is a key element of seismic hazard estimation. Many numerical methods in two dimensions are based on unstructured triangular meshes and explicit time schemes. However, the presence of thin layers and tangential stratigraphic contacts in sedimentary basins entails poorly shaped mesh elements: some triangle heights are extremely small compared to the edge lengths, which requires small time steps in the simulations and thus leads to prohibitive computation times. We compare manual and automatic geological model simplification techniques to modify problematic areas of the domain, so as to improve the quality of the triangulated mesh. We modify the shape and the connectivity between rock units in the basin, with the objective to reduce the computation time without significantly changing the physical response of the geological medium. These simplification techniques are applied in an investigation of site effects in the lower Var valley, a densely urbanized area located near the city of Nice (southeast of France). Numerical simulations of plane wave propagation in a heterogeneous 2-D profile are carried out with a discontinuous Galerkin finite element method. Five simplified meshes are generated and the impacts of the simplifications are analysed in comparison to the reference model. We compare the time solutions and the transfer functions obtained on the surface of the basin. The results show that the simplification procedures, in particular automatic modifications of the model, yield a significant performance gain, with a ratio higher than 55, while having a negligible impact on the ground motion response. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|