3D Frequency-Domain Elastic Wave Modeling Using Spectral Element Method with a Parallel Direct Linear Solver

Yang Li (1) , Romain Brossier (1) , Ludovic Métivier (1, 2)

1 ISTerre - Institut des Sciences de la Terre
2 EDP - Equations aux Dérivées Partielles

Complex topography, free surface boundary condition and inelastic properties of media should be well considered for onshore geophysical prospecting. Thus an appropriate and accurate forward modeling engine is very important. Unlike the time-domain implementation of many seismic imaging techniques, the counterpart in the frequency domain is rarely studied, despite of having many advantages, for example, only limited number of frequencies is needed for the inversion process, and solving the multiple-source problem is quite cheap if a direct solver is used. In this study, the spectral element method is applied to discretize the 3D frequency-domain anisotropic elastic wave modeling and the parallel direct solver MUMPS is used to solve the linear system. The structure and building process of the impedance matrix is thoroughly explained. We validate the numerical results by comparing with analytical solutions. A hybrid implementation of MPI and OpenMP for MUMPS is shown to be more efficient in flops and memory cost during the factorization. The influence of complex topography on MUMPS performance is negligible. With the available resources, the largest scale modeling, 30 wavelength in each dimension, is achieved. Other direct solvers and different low-rank techniques will also be investigated to reduce the flops and memory cost.

Domaines: Géophysique [physics.geo-ph]; Modélisation et simulation

Yang Li, Romain Brossier, Ludovic Métivier. 3D Frequency-Domain Elastic Wave Modeling Using Spectral Element Method with a Parallel Direct Linear Solver. 81st EAGE Conference and Exhibition 2019, Jun 2019, London, United Kingdom. ⟨10.3997/2214-4609.201901534⟩. ⟨hal-02325645⟩