改进的地震模型初值射线追踪方法

初值射线追踪方法是现代射线追踪方法中的一个很重要的理论,它克服了两点法射线追踪方法耗时的计算效率问题。以程函方程为基础,对初值射线追踪方法进行改进,即利用平方慢度来替换模型中的速度参数,使得程函方程产生解析解,从而进一步导出当射线遇到界面时的反射和透射慢度向量的计算表达式,以及反射、透射系数的函数表达式。通过对简单的两层界面向斜模型及复杂的多层盐丘模型的射线追踪,表明该初值射线追踪方法的改进相比于以往的龙格库塔离散数值解法,不但使射线追踪效率得到了大幅度提高（10倍左右）,且也扩大了射线法使用范围。

Improved Seismic Model Initial Value Ray Tracing Method

The initial value ray tracing method is one of major method in modern ray tracing methods.It overcomes time-consuming computing efficiency in two spots ray tracing.Based on eikonal equation,improved initial value ray tracing,that is using square slowness to replace velocity parameters in model,make eikonal equation produces analytic solutions,a step further to derive computing expressions of reflection and transmission slowness vectors when the ray confront with interface,and reflection and transmission coefficients function expressions.Through ray tracings of simple two layered interface syncline model and complex multiple layered salt-dome model,have shown the improvement of initial value ray tracing by comparison with Runge-Kutta discrete numerical solution,not only improved ray tracing efficiency（about 10 times）,but also extended limit for the use of ray tracing method.