三角网格中地震波初至旅行时的计算

Computation of seismic first-arrival times in triangular grid cells

本文提出一种在三角阿格中计算地震波初至旅行时的精确、快速新算法。在正三角网格中，我们给出了求解程函方程的有限差分格式，并采用扫描算法计算出模型中离散网格点上的精确初至时间。该方法易于实现并行计算。算法中考虑了透射波、散射波及首波。因此，对于速度任意变化的模型都能得到较好的计算结果。

We recommend an accurate fast new algorithm for computing the seismic first arrival times in triangular grid cells. In regular triangular grid cells,we use finite dif-ference scheme for solving eikonal equation,and cornpute the accurate first arrival times at discrete grid knots in model by scanning. The algorithm favours parallel computation. The procedure considers the existence of transmitted wave, scattered wave and head wave- As a consequence,satisfactory results can be obtained in the computation of the models which have various velocity variations.