1987年1月8日甘肃省迭部5.9级地震

THE DIEBU EARTHQUAKE OF M = 5. 9 ON 8 JAN. 1987

1987年1月8日甘肃省迭部县5.9级地震是继1954年山丹71/4级地震后,30余年来甘肃省境内发生的最大的一次地震。经过宏观考察和研究确定,其宏观震中位于光盖山—迭山主峰南竹路沟脑处,地理位置为北纬34°14＇,东经103°18＇。震中烈度为Ⅶ度。极震区为—近东西向展布的椭圆形区域,面积为300平方公里。有感范围达12000平方公里。该次地震发生在青藏高原北部的武都—玛曲断裂带内,其发震构造为北西西向具压性的向南陡倾的杂列括—桑巴沟脑断裂,本区内北东向的安子库断裂亦参与了活动。

The Diebu earthquake of Gansu Province on 8 Jan. 1987 has been the largest one in Gansu Province since the 1954 Shandan earthquake of M = 71/4 occurred more than thirty years ago.Based on field investigation, the macroscopic epicentre was determined. It is located near the head of Zhulu gully at the main peak of Guanggaishan and Dieshan mountains, locating at latitude 34°13' N and longitude 103°18'E.The epicentre intensity is Ⅶ and its meizoseismal area takes shape of ellipse which extends about east-west direction, with an area of about 300 km2.Nobody was injured and no houses collapsed because this event took place at high mountian forest district and there are few people lived there.The earthquake (M = 5. 9 ) occurred within Wudu-Maqu fault zone in the northern section of Tibetan Plateau, and the generating structure is the Zaliekuo-Sangbagou fault striking NWW and steeply dips towards south with compressional characteristics. This event was the result of the newest action of Zaliekuo-Sangbaguo fault.According to the. spacial distribution of aftershocks, another noticed evidence is that the Anziku fault striking NE in the region also took part in this earthquake activity.