有限差分波动方程正演模拟中的吸收边界条件

Absorbing Boundary Condition in the Finite Difference Wave Equation Forward Modeling Simulation

在地震波传播的数值模拟过程中,在有限的区域内建立吸收边界条件是一个很重要的问题。主要运用有限差分的方法对二维声波方程进行正演模拟,介绍并分析了利用有限差分的方法进行波动方程正演模拟过程中的几种吸收边界条件。先通过理论阐述,然后通过建立均质模型和层状介质模型来研究不同吸收边界条件下的边界吸收效果,得到对应的波场快照和单炮记录,并加以比较。通过实际验证得知当运用完全匹配层(PML)吸收边界条件时吸收效果最好,基本上不产生虚假反射。

In the numerical simulation of seismic wave propagation, absorbing boundary conditions established within the limited area is a very important issue. In this paper, the finite difference method was used to carry out two-dimensional acoustic wave equation forward modeling; some absorbing boundary conditions in the simulation process were introduced and analyzed. Through first theoretical explanations and then the establishment of a homogeneous model and layered media model, the boundary absorption effect of different absorbing boundary conditions was studied, and the corresponding snapshot of the wave field and shot record were obtained and compared. The practices show that, when using perfectly matched layer （PML）absorbing boundary conditions, the absorption effect is the best, which does not produce a false reflection basically.