(1. 中南大学 有色金属成矿预测教育部重点实验室，长沙 410083；
2. 中南大学 地球科学与信息物理学院，长沙 410083)
摘 要: 从改进BISQ模型双相介质所对应的一阶速度—应力运动方程出发，构建2×2N阶交错网格有限差分模拟算法，为了尽可能地减小或消除数值模拟中由人工边界引起的虚假反射，建立完全匹配层(PML)吸收边界的2×2N阶交错网格有限差分算法。详细地讨论了PML吸收边界条件的构建及其有限差分算法的实现。通过MATLAB编程进行波场模拟，将加入PML吸收边界、常规指数衰减吸收边界及未加吸收边界的3种数值模拟结果进行对比，论证PML吸收边界能十分有效地吸收边界反射。
关键字: 改进BISQ模型；双相介质；有限差分；交错网格；完全匹配层(PML)
seismic waves based on reformulated BISQ model
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China）
Abstract:Based on first-order velocity-stress equations of the reformulated BISQ model in double-phase media, the simulation algorithm of finite difference of 2-order time and 2N-order space staggered-grid was built. Meanwhile, in order to minimum effects caused by the artificial boundary in the numerical simulation, the construction of the perfectly matched layer (PML) absorbing boundary condition and the realization of the finite-difference algorithm were discussed in detail. The arithmetic was realized with MATLAB. Compared with the conventional decaying exponential absorbing boundary and the non-absorbing boundary, the PML boundary can more effectively attenuate reflections, which is supported by the wave field modeling.
Key words: reformulated BISQ model; double-phase medium; finite-difference method; staggered-grid; perfectly matched layer (PML)
