QSHA-WP3, Réunion du 23/11/20061 Projet QSHA –WP3 Laboratoire Central des Ponts et Chaussées 58,...

QSHA-WP3, Réunion du 23/11/2006 1

Projet QSHA –WP3

Laboratoire Central des Ponts et Chaussées

58, bd Lefebvre, 75732 Paris Cedex 15

http://www.lcpc.fr

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


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 Europethrough 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


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 setand

Source Dynamics (SD) model set

Both model sets are divided into three subsets

Obviously, new models can/will be addedin correspondence

with progress in the numerical modeling methods


SPICE Subset WP I

Simplest canonical models

designed 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 errorhomogeneous viscoelastic space : incorporation of attenuation2 homogeneous halfspaces : planar interface

- elastic interface - viscoelastic/pure_Q interface

homogeneous halfspace : planar free surfacehomogeneous anisotropic el. space : anisotropy


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 / Qrandom 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


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)


Quantitative Misfit CriteriaEach submitted solution can be compared

with 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 & PM

misfit criteriawere developed by

Kristekova, Kristek, Moczo and Day( Bull. Seism. Soc. Am. 2006, #5 )

The criteria are based on

the time-frequency representation of seismograms

The time-frequency representationis obtained using the continuous wavelet transform


Interactive web interface

The interactive web interface

http://www.nuquake.eu/SPICECVal

has been developed by the SPICE teamat the Comenius University in Bratislava


The SPICE Code Validationprovides

an 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…)


WP3 - Ground motion simulation


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

Developments of numerical tools for wave propagation


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

6/7 methods !!


Tableau récapitulatif méthodes

Groups FDM FEM SEM FVM BEM DEM EGF

GEOAZUR L L NL

LGIT L/(NL) NL

BRGM L L/EQ/NL

NL NL

CEA ? L/NL ?

LCPC L/EQ/NL

L/NL L NL

L=linear, EQ=equivalent linear, NL="non-linear"


Simple canonical models

• 2D/3D,• Stratification,• Amortissement,• Discrétisation, extension géométrique...• Comportement…

…• finally simple structures : canyons, basins (for

purpose of validation), cf Sismovalp


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...)


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


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...


WP3-5 Statistical comparison(Hideo Aochi)

• Variability of simulations using intensive simulations...


WP 3-6 Lessons (J.Virieux)

• ????


WP 3-X ...

2006-1 2006-2 2007-1 2007-2 2008-1 2008-2

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Planning et échéancier !

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QSHA-WP3, Réunion du 23/11/20061 Projet QSHA –WP3 Laboratoire Central des Ponts et Chaussées 58,...

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