Multiple ray tracing within 3-D layered media with the shortest path method
最短路径算法下三维层状介质中多次波追踪

The purpose of this study is to introduce a multistage scheme incorporating the modified shortest-path method (MSPM) for tracking multiple arrivals and simulating wavefront evolutions composed of any kind of combinations of transmissions, conversions and reflections in complex 3-D layered media. The principle is first to divide the layered model into several different computational domains, and then to use the multistage technique to trace the multiple arrivals. It is possible to realize the multiple arrival tracking with the multistage technique because the multiple arrivals are different combinations or conjugations of the simple incident, transmitted and reflected waves at the velocity boundaries (or discontinuities). Numerical tests and error analysis indicate that the multistage MSPM method retains the basic characteristics of the single-stage MSPM approach, that is algorithm simplicity, numerical stability, high computational accuracy, fast, global solution and etc. Therefore it is a practical algorithm to track the multiple arrivals.