Based
    on the pseudo spectral 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. 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.