可变网格与局部时间步长的交错网格高阶差分弹性波模拟

交错网格高阶差分方法是一种在保持效率的前提下提高弹性波模拟精度的有效方法.本文将可变空间网格与变化的时间步长技术引入到交错网格高阶差分弹性波模拟中，提出一种空间网格可任意奇数倍变化与时间步长任意变化的交错网格高阶差分弹性波模拟方法.一系列数值试验表明，该方法能够在保证模拟精度的同时，通过有效降低空间与时间维度上的过采样来显著提高弹性波模拟的效率.同时，该方法还能够精细刻画含孔缝洞介质以及横向变化剧烈介质的局部细微结构，减小弹性波模拟误差，提高介质细微结构处的弹性波传播模拟精度.

Staggered-grid high-order finite-difference method in elastic wave simulation with variable grids and local time-steps

Accuracy and efficiency are most urgent problems in elastic wave simulation. Staggered-grid is an effective method to improve the accuracy with high efficiency. By the combination of variable spatial grids and locally variable time-steps, a staggered-grid high-order finite-difference method with oddly arbitrarily variable spatial grids and arbitrarily variable local time-steps is presented. The numerical results show that the simulation accuracy and efficiency are raised effectively by removing oversampling both in space and time domain. Additionally, compared with the traditional method, this modeling method has advantages of simulating seismic wave propagation in the media with fractures, caves and complicated structures. It can describe such media in details, and has high accuracy and efficiency.