长江三峡地区地震的远距离独立烈度异常区

一、前言长江三峡蕴藏着极其丰富的水利资源,为我国当前最大的水利电力枢纽工程所在地。这里地震工作开展较早,本世纪二十年代以来,中外地学界曾在此进行了多方面考察。新中国成立后,在着手规划开发长江水利资源的初期,己布设了三峡地震台网,同时开展了地震地质调查和地形变观测工作。笔者在峡区周围曾参加过多次地震考察,发现黄陵背斜东西两侧地震时,在远离震中的钟祥和荆门地区出现等震线单独封闭的独立烈度异常区。在等震线分布

A REMOTE ABNORMAL SEISMIC INTENSITY OF THE EARTHQUAKES IN THE SANXIA AREA

The main parameters and microscopic phenomena of the four particular earthquakes occurred in the area of the Sanxia area have been introduced in this paper. These earthquakes seem to have two macroscopic epicenters of which the cause of the formation must be much complicated. The area of the Three Gorges is located in the gravity gradient zone in the east of China and the Moho here is rather declivitous. Thus, the single abnormal region of seismic intensity at a distance from the epicenters may occur because seismic reflection waves are focused and reflected by the Moho discontinuity.