1996年11月9日长江口外6.1级地震影响场与震中区地震地质概述

Seismic Influence Field andGeological Background of the Earthquake(m= 6. 1,Nov. 9,1996) Ocurred in theFront of the Yangtze River Mouth

1996年11月9日长江口外6.1级地震震中位于北纬31°43’,东经123°04’震级(Ms)6.1级,震源深度7km,陆上最大地震烈度为4度。上海虽普遍有感,但无明显损失。在解译长江口外地球物理场异常的基础上,发现这次地震发生在东西向崇明—启东断裂与北东向镇海断裂的交汇部位,是北东向断裂右旋滑移的结果。

The earthquake(M = 6. 1.Nov. 9,1996)is ocurred in the front of the Yangtze River mouth (31°43'N,123°04'E).The depth of focus is 7km,and the maximum intensity in land is IV. It is generally perceptible in Shanghai,but there is no damage. In this paper,on the basis of analysing the geophysical field in this area, it is found that this earthquake is ocurred in intersection zone of two faults, the Chongming Qidong fault (EW)and Zhenhai fault (NE). The right slip of the fault (NE) results in ocurrence of the quake. The classification of the earthquake is solitary shock type.