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Projet QSHA –WP3 . Réunion du 23/11/2006. Laboratoire Central des Ponts et Chaussées 58, bd Lefebvre, 75732 Paris Cedex 15 http://www.lcpc.fr. Réunion WP3 : ordre du jour. 10h-12h : Méthodes et évolutions envisageables Différences finies, Jean Virieux Éléments finis, Evelyne Foerster
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Projet QSHA –WP3 Réunion du 23/11/2006 Laboratoire Central des Ponts et Chaussées 58, bd Lefebvre, 75732 Paris Cedex 15 http://www.lcpc.fr QSHA-WP3, Réunion du 23/11/2006
Réunion WP3 : ordre du jour • 10h-12h : Méthodes et évolutions envisageables • Différences finies, Jean Virieux • Éléments finis, Evelyne Foerster • Éléments spectraux, Emmanuel Chaljub • Volumes finis, Nathalie Glinsky • Éléments de frontière (FMM), Stephanie Chaillat • Éléments discrets, Christian Mariotti • Fonctions de Green empiriques, Carine Kohrs-Sansorny • Modèles de comportement non linéaires, Fabian Bonilla • 12h15-13h : Benchmark ESG + Sismovalp + Spice (+SCEC?)Emmanuel Chaljub, Seiji Tsuno et Jean-François Semblat • 14h-17h : Discussion pour QSHA-WP3 : • modèles géologiques et liens avec WP1, Cécile Cornou • modèles numériques canoniques et réalistes • sensibilité aux paramètres, comparaisons repas QSHA-WP3, Réunion du 23/11/2006
Projet européen SPICE Seismic Wave Propagation and Imaging in Complex Media:a European Network (SPICE) one of the primary goals : Development of the earthquake motion numerical simulation methods code validation effort in Europe through a long-term web-interactive basis for possible tests/comparisons/validationof numerical methods and codesfor the seismic wave propagationand earthquake motion simulation The basis will serve even after the SPICE projectis completed and to anybody interested QSHA-WP3, Réunion du 23/11/2006
Two model sets Based on the evaluation of the SCEC code validation projectand capabilities of recent numerical-modeling methods,two model sets were elaborated: Wave Propagation (WP) model setandSource Dynamics (SD) model set Both model sets are divided into three subsets Obviously, new models can/will be addedin correspondencewith progress in the numerical modeling methods QSHA-WP3, Réunion du 23/11/2006
SPICE Subset WP I Simplest canonical modelsdesigned to test accuracy of the methods/codeswith respect to individual factors/features of the models: (includes SCEC_UHS1 and SCEC_UHS2) homogeneous elastic space : dispersion, local error homogeneous viscoelastic space : incorporation of attenuation 2 homogeneous halfspaces : planar interface - elastic interface - viscoelastic/pure_Q interface homogeneous halfspace : planar free surface homogeneous anisotropic el. space: anisotropy QSHA-WP3, Réunion du 23/11/2006
SPICE Subset WP II Canonical modelscombining two or more basic individual factors/features: (includes SCEC_LOH1 and SCEC_LOH3) layer over halfspace : planar interface + free surface - elastic and viscoelastic - source inside layer / halfspace gradient in velocity / Q random velocity distribution soft inclusion in a halfspace : lateral heterogeneity vertical layer in a halfspace: interface at the free surface 2 homogeneous halfspaces : non-planar interface free-surface topography : traction-free condition - Gaussian hill - cliff - slope QSHA-WP3, Réunion du 23/11/2006
SPICE Subset WP III Realistic models possibly with real recordings: (includes SC_2.1 and SC_2.2 ) Colfiorito, Central Italy : laterally bounded sedimentary basin (in cooperation with the INGV Rome, Italy) Grenoble, France : deep Alpine valley (in cooperation with the ESG 2006 Grenoble benchmark organizers) other site(s) QSHA-WP3, Réunion du 23/11/2006
Quantitative Misfit Criteria Each submitted solution can be comparedwith a reference solution for a given problem,and with other submitted solutions,using the quantitative misfit criteria TFEM & TFPM, TEM & TPM, FEM & FPM,and single-valued EM & PMmisfit criteriawere developed byKristekova, Kristek, Moczo and Day( Bull. Seism. Soc. Am. 2006, #5 ) The criteria are based onthe time-frequency representation of seismogramsThe time-frequency representationis obtained using the continuous wavelet transform QSHA-WP3, Réunion du 23/11/2006
Interactive web interface The interactive web interface http://www.nuquake.eu/SPICECVal has been developed by the SPICE teamat the Comenius University in Bratislava QSHA-WP3, Réunion du 23/11/2006
The SPICE Code Validationprovidesan unprecedented opportunity in Europe(and possibly not only in Europe)to test and compare methods and computer codesfor modeling of seismic wave propagation,earthquake ground motion, and seismic exploration Participants au projet SPICE favorables à échanges avec autres projets et contributions supplémentaires à l’effort de validation (cas tests, solutions de référence…) QSHA-WP3, Réunion du 23/11/2006
WP3 - Ground motion simulation QSHA-WP3, Réunion du 23/11/2006
WP3-1 Methological improvements Developments of numerical tools for wave propagation Main goals : • main features of the various methods (table) • current or potential improvements • range of application (frequency, heterogeneity, non linearity…) • comparisons (misfit criteria) : • efficiency • accuracy • stability… • very simple canonical models with well constrained features QSHA-WP3, Réunion du 23/11/2006
Fiche descriptive / méthode • Type/name of method: FVTD - Finite-Volume Method in the Time Domain • Contributors (labs):N. Glinsky-Olivier (Cermics/INRIA), S. Lanteri (INRIA), M. Benjemaa (INRIA), S. Piperno (Cermics/INRIA), J. Virieux (GeoSciences Azur), • Basic principle & improvements: • Principles : Finite Volumes, Unstructured grids, Centered numerical fluxes, Leap-frog time-scheme, Energy conservation, Weak treatment of boundary conditions (free surface, ABC, dynamic rupture) • Improvements : extension using Discontinuous Galerkin Finite Elements, parallel solver in development • Features: • Source/propagation (S, P, S+P): S+P • Coupled methods: coupling with PML, poss. coupling with FETD & FDTD meth • 1D/2D/2.5D/3D : 2D (3D parallel solver under development) • Time/frequency: time-domain • Direct/iterative: direct (explicit in time) • Elements size (fraction of l): 1/12 in FVTD (less in DGTD) • Model size (nb of l): • Free-surface topography: Yes • Heterogeneity: Yes • Anisotropy: Yes (future) • Material behav. (lin., NL, eq.lin): linear • Damping (NCQ, rheol.): none (possible) • Main references 6/7 methods !! QSHA-WP3, Réunion du 23/11/2006
Tableau récapitulatif méthodes L=linear, EQ=equivalent linear, NL="non-linear" QSHA-WP3, Réunion du 23/11/2006
Simple canonical models • 2D/3D, • Stratification, • Amortissement, • Discrétisation, extension géométrique... • Comportement…… • finally simple structures : canyons, basins (for purpose of validation), cf Sismovalp QSHA-WP3, Réunion du 23/11/2006
WP3-2 Sensitivity studies (P-Y Bard) • Key parameters in modelling : • intermediate canonical models (for sensitivity analyses) • influence of topography description • sensitivity to source location, source dynamics, source extension… • influence of soil non linearities in 2D and 3D • influence of the physical model (variability) on response spectra (input uncertainties vs output uncertainties) • identification of the key parameters to be measured • finally, empirical description of the physical effects from theoretical results(e.g. 2D/3D aggravation factor...) QSHA-WP3, Réunion du 23/11/2006
WP3-2 Sensitivity studies (P-Y Bard) (Nearly) realistic models : • Nice (WP1 : test de rugosité d’interface…) • Grenoble • Algiers • Naples……cf WP3-3 & WP3-4 QSHA-WP3, Réunion du 23/11/2006
WP3-3-WP3-4 Benchmarking (E.Chajlub/E.Foerster) • Validation of developed codes based on international benchmark but not tied to ESG2006 with two geometries (Basins and margins) • Fully realistic models... QSHA-WP3, Réunion du 23/11/2006
WP3-5 Statistical comparison(Hideo Aochi) • Variability of simulations using intensive simulations... QSHA-WP3, Réunion du 23/11/2006
WP 3-6 Lessons (J.Virieux) • ???? QSHA-WP3, Réunion du 23/11/2006
WP 3-X ... Planning et échéancier ! Prochaine réunion ? QSHA-WP3, Réunion du 23/11/2006