地震射线辛几何算法初探

走时计算已广泛用于地震建模、成像及速度分析等诸方面．基于地震波场的Ｈａｍｉｌｔｏｎ力学性质，本文探索应用适于Ｈａｍｉｌｔｏｎ力学的计算方法──辛几何算法对地震射线 进行走时及路径的计算．利用辛几何算法和属于耗散算法的四阶 Ｒｕｎｇｅ－Ｋｕｔｔａ算法进行射线 路径和走时的计算对比，结果表明这两类算法数值精度相当，但辛几何算法的速度却快了３ 倍．本文还利用二阶Ｅｕｌｅｒ型辛差分格式对Ｍａｒｍｏｕｓｉ模型进行了射线追踪计算，结果显示所 得射线具有良好的光滑性和较强的阴影区穿透能力．

AN ATTEMPT TO SEISMIC RAY TRACING WITH SYMPLECTIC ALGORITHM

Traveltime-computation is widely used in seismic modeling, imaging and velocity analysis, etc. The technology of ray tracing is one of the common methods to acquire traveltime. With the development of the research in complex geology and considering Hamilton mechanics quality of seismic wave field, the symplectic algorithm which is based on Hamilton mechanics is used to obtain traveltime and path of Seismic ray in this paper. The traveltime and path obtained by both Symplectic algorithm and Runge-Kutta algorithm belonging to dissipative algorithm are compared. The result indicates the precision of both is very adjacent however the Symplectic algorithm is far more faster. In addition, the ray tracing have been carried on complex Marmousi Model. The result has proved that Symplectic algorithm is a preferable robust and has a better ability to penetrate shadow zones.