SEISMIC WAVEFIELD SIMULATION WITH IRREGULAR SURFACE TOPOGRAPHY AND GRAPHIC PROCESSING UNIT (GPU) IMPLEMENTATION

摘要

Seismic wavefield simulation in the presence of surface topography provides important information for characterizing seismic wave propagation. Based on the boundary-conforming grid method, we first transform both elastic wave equations in second-order formulation and free surface boundary condition in first order system from Cartesian coordinates to curvilinear coordinates. Then, the convolutional perfectly matched layer (CPML) boundary condition is applied to absorb the outgoing seismic waves at the edges of the truncated model. The test results (e.g., wavefield snapshots and seismograms) show that our numerical algorithms can effectively simulate seismic wave propagation in a model with rough topography, and CPML is more efficient than perfectly matched layer (PML) boundary condition in suppressing artificial reflections. In addition, the finite-difference algorithms on a single Graphic Processing Unit (GPU) are used to accelerate seismic numerical modeling in both elastic isotropic and anisotropic media. Compared with the conventional CPU version, the GPU implementation greatly reduces the computational cost.