地震波传播的三维伪谱和高阶有限差分混合方法并行模拟

基于交错网格伪谱法和高阶精度有限差分方法，发展了模拟非均匀介质地震波传播的三维伪谱和有限差分混合算法.该方法在两个水平方向利用交错网格伪谱算子计算空间微分，保留了该方法高效、高精度的优势，在垂直方向采用交错网格高阶精度有限差分算子实现空间微分计算．利用有限差分方法的局部性特征，将三维计算区域在垂直方向上划分为一系列子区域，并分配给不同的处理器，实现了在并行计算机集群上的三维并行计算．通过模拟算例，与离散波数法比较，检验了该算法的精度．为了检验该方法的实用性，在64个处理器上，对三维沉积盆地模型进行了67108864个网格点的并行计算，模拟的波场主频率为1.25Hz，讨论了沉积盆地深度对三维沉积盆地地面运动的影响． 

Three-dimensional parallel hybrid PSM/FDM simulation of 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.