垂向非均匀介质的走时反演

TRAVEL-TIME INVERSION OF THE VERTICALLY INHOMOGENEOUS MEDIUM

摘要:

本文提出了一种利用反射波走时曲线计算垂向非均匀介质速度和反射界面深度的方法。当在地球表面没有获得来自地下某一深度范围内介质的任何信息时,可以认为这一深度范围内的地震波速度具有连续性。利用来自其底部反射界面的反射波走时曲线,可以计算出该深度范围的地震波速度结构。
对三种模型进行了理论计算,所得反演解与真实值较为一致,其中计算出的反射界面深度最为精确。利用本文提出的方法可以计算两个相邻反射面之间的垂向非均匀速度结构,如低速层等。

Abstract:

A method is presented, which makes it possible to calculate velocity and interface depth of the reflected wave in a vertically inhomogeneous medium. When no information from some depth range of the earth interior is received on the earth surface, the seismic wave velocity in this depth range is considered continuous and can be computed using the travel-time curve of the reflected wave of its bottom interface. Three models are studied and a good result is obtained, in which the reflected interface depth is satisfactory. As phase comparison cannot be done in most artificial seismic data, it is difficult to find the evidence for the existence of low velocity layers. The method presented here provides a solution to this problem.