起伏地表条件下二维地震波场的数值模拟

地震波场数值模拟一般基于水平地表条件，而当前近地表地震方法研究中急需起伏地表条件下的正演模拟数据。起伏地表条件下的二维地震波场波动方程高阶有限差分数值模拟方法研究中面临的主要问题是边界条件的处理。从以速度应力表示的一阶波动方程出发，导出了起伏边界情况下的边界条件。该条件与波动方程具有相同的形式，可以用同样的方法来处理正演过程中的网格内部点和边界点。用交错网格的高阶有限差分方法解波动方程，在满足稳定性要求时，可获得时间和空间都是高阶精度的结果。本算法在高性能计算机集群MPI环境中并行实现时，采用主从模式设计程序，合理调配各节点的计算负载，并应用容错处理手段，达到了较高的并行效率。理论模型和实际速度模型的计算结果证明了方法的正确性和有效性。

Numerical modeling of 2-D seismic wavefield under ragged surface

Numerical modeling of seismic wavefield is generally based on horizontal surface. In case of ragged surface, proper handling of boundary conditions poses great challenge in high order finite difference wave equation numerical modeling of 2-D seismic wavefield. Starting from one-order wave equation, we derived boundary conditions under ragged surface. The boundary conditions have the same expression with wave equation, and can manipulate both internal points and boundary points with the same means. Highly precise solutions both in time and in space can be reached by solving wave equation with high order finite difference scheme of staggered grid under the condition of stability. The method was realized in powerful cluster MPI computing environment using master-slave model. Strategies of load relocation on different nodes and fault-tolerance were adopted. The correctness and effectiveness of the method was demonstrated on theoretical and real data.