摘要
1973年2月6日,四川省甘孜藏族自治州炉霍县发生了7.9级强烈地震,震中烈度为10度,通过震中区沿鲜水河谷产生了长达90公里的地震裂缝带。裂缝以张扭性的为主,伴有少量压性和扭性结构面,其组合型式有反“多”字型、斜列式、锯齿状和棋盘格式等四种,反映的运动方式以水平运动为主,最大水平错距达3.6米,垂直落差都在20—30厘米。本文着重研究了这次地震所产生的各种类型地裂缝的力学特征,结合地质构造背景探讨了地震区应力作用方式及地震成因。从地震裂缝带出现的位置、力学性质、活动方式与鲜水河断裂相一致来看,这次地震是鲜水河断裂的最新活动,是该断裂运动的必然结果。
A strong earthquake(M=7.9)occurred in the Lu-huo county,Ganzi Zang Autonomous Zhou,Sichuan Province,on Feb.6,1973.Its epicentral intensity is 10.The earthquake fracture zone passing through the epicentral region extends to 90 km along the Xian-Shui Eiver(鲜水河)valley.Fractures are principally of the tensile-torsional type accompanied by a few structural planes of compression find torsion.There are four types of fracture patterns in combination,namely:reversed"ξ"type,oblique type,sawtooth type and grid type.They reflect mainly horizontal movements.The maximum horizontal displacement is 3.6m,while,vertical throws amount to 20-30 cm.In this paper we try to investigate the mechanics of every type of ground fractures created by this earthquake,and in combination with the existing geological background to discuss the stress in this earthquake region and the-origin of the earthquake.From the fact that the position of the earthquake fracture zone,its mechanics and movements are rather similar to that of the Xian-Shui Eiver fault,it can be inferred that the Lu-huo earthquake represents the most recent activity,ofXian-Shui Eiver fault,and should be the necessary result of its movement.
作者
唐荣昌
文德华
邓天岗
黄圣睦
TANG RONG-CHANG;WEN DE-HUA;DENG TIAN-GANG;HUANG SHENG-MU(The Seismological Brigade of Chengdu,National Seismological Bureau)
出处
《地球物理学报》
1976年第1期18-27,71-74,共14页
Chinese Journal of Geophysics
