1. QSHA, Réunion du 01/06/20071 Projet QSHA – WP3 Laboratoire Central des Ponts et Chaussées 58, bd Lefebvre, 75732 Paris Cedex 15 http://www.lcpc.fr Réunion du 01/06/2007

2. QSHA, Réunion du 01/06/20072 WP3 - Ground motion simulation

3. QSHA, Réunion du 01/06/20073 WP3-1 Methological improvements 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 (and simple sources) Developments of numerical tools for wave propagation

4. QSHA, Réunion du 01/06/20074 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 ): 1/12 in FVTD (less in DGTD) –Model size (nb of ): –Free-surface topography: Yes –Heterogeneity: Yes –Anisotropy: Yes (future) –Material behav. (lin., NL, eq.lin): linear –Damping (NCQ, rheol.): none (possible) –Main references à remplir pour S3 !!

5. QSHA, Réunion du 01/06/20075 Tableau récapitulatif méthodes GroupsFDMFEMSEMFVMBEMDEMEGF GEOAZUR LLNL LGIT L/ (NL) NL BRGM LL/EQ/ NL NL CEA ?L/NL? LCPC L/EQ/ NL L/NLLNL L=linear, EQ=equivalent linear, NL="non-linear" à compléter/corriger…!

6. QSHA, Réunion du 01/06/20076 Simple canonical models Simple canyons/basins : –2D (SismoValp) : 1 asymmetrical models + higher frequencies … is it useful to choose other 2D models ? –3D (mainly semi-spherical, asymmetric) Simple sources (plane waves, points sources…) Analyze efficiency/accuracy taking into account : –Damping/attenuation, –Discretization, geometrical extent... –Constitutive laws –Simple stratification, –… Possible link with/contribution to Spice database (http://www.nuquake.eu/SPICECVal) choice among existing models in the database ?!

7. QSHA, Réunion du 01/06/20077 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...)

8. QSHA, Réunion du 01/06/20078 WP3-2 Sensitivity studies (P-Y Bard) (Nearly) realistic models : Nice (WP1 : test de rugosité dinterface…) Grenoble > modèle avec gradient + modèle à couches (pour BEM !) Algiers Naples… …cf WP3-3 & WP3-4

9. QSHA, Réunion du 01/06/20079 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) Simulations performed in the Nice zone including water layer Fully realistic models...

10. QSHA, Réunion du 01/06/200710 WP3-5 Statistical comparison (Hideo Aochi) Variability of simulations using intensive simulations related to model variations related to source variations

11. QSHA, Réunion du 01/06/200711 WP 3-6 Lessons (J.Virieux) To be done in S5 and S6 (2008) when comparing methods

12. QSHA, Réunion du 01/06/200712 WP 3-X... Rapport S3 : contributions à envoyer à semblat@lcpc.fr (y compris "fiche de synthèse" pour chaque méthode) Prochaine réunion : 2 ou 3 juillet 2007 (avant Colloque AFPS)