A massively parallel time‐domain discontinuous Galerkin method for 3D elastic wave modeling

Abstract

We present a massively parallel time‐domain Discontinuous Galerkin (DG) finite‐element formulation with Convolutional Perfectly Matched Layer (CPML) absorbing condition for 3D elastic seismic wave modeling with tetrahedral meshes. Parallelism is implemented by domain decomposition. The modeling is purposely developed for frequency‐domain full‐waveform inversion (FWI) in 3D elastic media. We designed an efficient and computationally‐efficient CPML absorbing condition by combining two interpolation orders in the computational domain: we used the DG scheme in the medium to get the required accuracy while we used the low‐order DG scheme in the CPMLs to reduce the whole numerical cost and to obtain a well‐balanced workload over processors. The use of the low‐interpolation orders has been driven by the theorical resolution of FWI, which constrains the spatial discretization of the medium, and hence, the required interpolation order. We applied the proposed method to the SEG/EAGE overthrust model. The measured computation times of the modeling provide clear insights on the feasibility of 3D elastic FWI.