Global SH-wavefield calculation for a two-dimensional whole-Earth model with the parallel hybrid PSM/FDM algorithm

We present a parallel hybrid algorithm based on pseudospectral method(PSM) and finite difference method(FDM) for two-dimensional(2-D) global SHwavefield simulation.The whole-Earth model is taken as a cross section of spherical Earth,and corresponding wave equations are defined in 2-D cylindrical coordinates.Spatial derivatives in the wave equations are approximated with efficient and high accuracy PSM in the lateral and high-order FDM in the radial direction on staggered grids.This algorithm allows us to divide the whole-Earth into sub-domains in radial direction and implement efficient parallel computing on PC cluster,while retains high accuracy and efficiency of PSM in lateral direction.A transformation of moment tensor between 3-D spherical Earth and our 2-D model was proposed to give corresponding moment tensor components used in 2-D modeling.Comparison of modeling results with those obtained by direct solution method shows very good accuracy of our algorithm.We also demonstrate its feasibility with a lateral heterogeneous whole-Earth model with localized velocity perturbation.