地震波走时的有限差分法计算

类似于Claerbout思想,将波动方程在射线理论中的对偶--镜像方程写为上、下行波方程的形式.对变换得到的守恒型偏微分方程,用E-O格式,可计算出任意速度构造的二维网格上各点的地震波走时.文中证明了守恒型偏微分方程的通量为一凸函数,采用单调的守恒型差分格式,精度符合要求.计算速度比目前所用的各种计算走时的方法都快得多,算法也便于向量化.

FINITE DIFFERENCE CALCULATION OF SEISMIC TRAVEL TIMES

Similar to Claerbout' s idea, it is possible to transform the counterpart of the full wave equation in ray theory, the Eikonal equation into the form of the upgoing and/or downgoing wave equations. By application of the Engquist-Osher scheme to the transformed conservative partial differential equation, we can compute the seismic travel times of any point in a mesh with any velocity structure. The paper proves that, the flux in the conservative partial differential equation 'is a convex function. The monotone conservative finite difference scheme with first-order accuracy we used here can satisfy the accuracy demands. Its computing speed is much faster than any other travel time computing algorithms currently used. And it is vectorizable.