有限差分法精确计算地震走时

快速精确计算走时在层析成像反演中起重要作用，本文采用有限差分法来计算。首先通过变换，将程函方程化成一守恒形式；然后再差分离散，得到一阶和二阶精度的差分格式，并证明了差分格式条件稳定。模型试算表明：本文算法简明稳定，能快速高精度地计算地震走时，是一种值得注意和采用的走时计算方法。

PRECISE CALCULATION OF SEISMIC TRAVEL TIMES BY FINITE DIFFERENCE METHOD

It is very important to calculate travel times rapidly and precisely in tomographic inversion. In this paper, the authors adopt a finite difference method. First, using some transformations, the authors obtain a conservation form from the Eikonal equation, and then not only give two types of finite difference schemes which have first order and second order accuracy respectively, but also prove that they are conditionally convergent. Numerical experiments show that the algorithms are concise and stable, and can calculate seismic travel times efficiently and accurately, so the method deserves to be considered and adopted.