Three-dimensional parallel hybrid PSM/FDM simulationof seismic wave propagation

Based on the pseudospectral method (PSM) and higher-order finite difference method (FDM) for staggered grid, this paper presents a 3D parallel hybrid PSM/FDM scheme to simulate seismic wave propagation in heterogeneous medium. The spatial derivatives in the wave equations for the two horizontal directions are calculated with the efficient and high accuracy PSM operator, while the vertical derivatives are calculated with a high-order FDM operator. The localized FDM operation in vertical direction enables us to divide the 3D model into subregions, which are assigned to different processors of a PC cluster for 3D parallel computation. The accuracy of this scheme was verified by comparing our result with that of using discrete wave number method. To show the feasibility of the parallel scheme, we performed parallel simulation for a 3D sedimentary basin to show the effect of basin depth on ground motion. The simulation is carried out on PC cluster with 64 processors for a 67108864 grids model. The dominated frequency for the simulated seismic wavefield is 1.25 Hz.