Abstract: The data are used to study the P_g phase of three DSS profiles in Yunnan Province, corrected by elevation and diving wave effect. At first, the inversion of their depths has been made by the time field method, then the velocity distribution along the top boundary of basement is evaluated by the sliding average method. The results show that the lateral variation of the boundary valocity is an important basis for investigation of the variation of the rock property. It is also a method to judge the existence and the character of faults. Where the lateral variation of the boundary velocity occurs suddenly there is usually some influence of the fault. Many faults in these profiles are in evidence this way. Some great faults are accompanied by depth changes of interfaces or distortions of the isochrones.

Key words: Yunnan Province, Shallow fault, Interface velocity, Sliding average method, Basement

摘要： 利用云南地区深地震测深3条剖面中经地形校正与回折波影响校正后的P_g震相资料,先用时间场法反演其界面深度变化。再以滑动平均法求出速度沿基底界面的横向分布。分析处理的结果表明,界面速度的横向变化为研究岩性横向变化提供了依据,也是判定断裂的存在及其性质的手段之一。在速度横向变化跳跃处往往存在断裂,某些大断裂在浅部还出现深度跳跃变化或等时间线分布畸变。

关键词: 云南省, 浅层断裂, 界面速度滑动平均法, 基底层