成县-西吉剖面地壳速度结构

THE VELOCITY STRUCTURE OF CHENGXIAN-XIJI PROFILE

摘要:

天水地震区人工地震测深工程中成县一西吉测线南起甘肃成县,北至宁夏西吉,全长242公里,设4个炮点。对该测线资料解释的结果表明,该测线地壳可分为沉积层、上地壳、中地壳与下地壳四层。莫霍面从南向北逐渐加深,在天水一秦安附近M面上隆,中地壳顶部发现有低速层。与测线相交的西秦岭北缘断裂是一个超壳断裂,该断裂是祁连地槽与秦岭地槽的分界断裂。

Abstract:

The Chengxian-Xiji profile of DSS in Tianshui earthquake area is from Chengxian country of province Gansu to Xiji country of Ningxia Hui Autonomous Region,the total length of profile is 242km with 4 shots.The crust can be divided into four layers,sedimentary,upper crust,middle crust and down crust.The deep of Moho increase gradually from south to north,and it rises in the vicinity of Tianshui-Qinan.The low velocity layer (LVL) was found in the top of middle crust.The northern fringe fault of western segment of Qinling Mountain across to the profile is a over-crust fault and it is a boundary fault between Qilian and Qinling Geosyncline.