一种基于Snell定理反演二维斜界面的几何方法

A geometric algorithm based on Snell theorem for the inclined interface inversion in two-dimensional space

在二维情况下,如果地质结构的分界面为一条有固定斜率的斜线,则反演该界面时所需要确定的参数可以归结为两个:一个是界面上的反射点,另一个是界面的斜率。依据Snell定理,利用源点与反射波最短路径点之间的几何关系,导出一种快速反演斜界面的方法。作为算例,首先利用时域有限差分法对一个二维倾斜界面模型进行了数值模拟,而后利用该方法进行反演,界面位置误差在1%以内。

In two-dimensional space, if an interface of geologic structure has one fixed slope, then only two parameters needs to determined for the inversion of the interface. One is a reflect point in it, and another is the slope. Using the geometrical relationship between the source point and the fastest travel point of the reflect wave, a quick inversion algorithm was gained based on Snell theorem. At last, some examples of numerical simulation were given and it is very good. The inversion data was got from a two-dimensional model with a slope interface using FDTD.