HR: 0800h
AN: S21C-0714    [Abstracts]
TI: Homogenization of the SH-Wave Equation in 2D Heterogeneous Media
AU: * Guillot, L
EM: guillot@ipgp.jussieu.fr
AF: Department of Seismology, Institut de Physique du Globe de Paris, 4 place Jussieu, Paris, 75005, France
AU: Capdeville, Y
EM: capdevil@ipgp.jussieu.fr
AF: Department of Seismology, Institut de Physique du Globe de Paris, 4 place Jussieu, Paris, 75005, France
AU: Marigo, J
EM: marigo@lmm.jussieu.fr
AF: Laboratoire de Modelisation en Mecanique, Universite Paris 6, 4 place Jussieu, Paris, 75005, France
AB: In the Earth, seismic waves propagate through 3-dimensional heterogeneities characterized by a large variety of scales, much smaller than their minimum wavelength. Computing the wavefield in such media with the use of heavy numerical methods, leads to high calculation costs. To lower these latter, but also to obtain a better geodynamical interpretation of tomographic images, we aim at calculating convenient effective properties of heterogeneous media, by deriving appropriate upscaling rules for the wave equation. To progress towards this goal, we extend the successful work of Capdeville and Marigo (2007), from 1-D to 2-D; basically, we apply the so-called homogenization method -based on a two-scale asymptotic expansion of the field variables-, to model wave propagation in 2-D periodic media. These are characterized by short-scale variations of elastic properties, compared to the smallest wavelength of the wavefield. Seismograms are obtained using the 0th-order of this asymptotic expansion, at a lower computational cost. They are in good agreement with reference solutions calculated with spectral elements simulations, at least in the bulk of the medium. We finally suggest an extension of the homogenization of the wave equation, to 2-D nonperiodic, deterministic media.
DE: 7200 SEISMOLOGY
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2007 Fall Meeting