渭河盆地及邻区现今地壳形变及构造特征研究

Current Crustal Deformation and Tectonic Characteristics of Weihe Basin and Its Adjacent Areas

摘要:

基于2009-2014年渭河盆地及邻区GPS资料，利用Shen提出的连续形变场与应变场计算方法，获得渭河盆地及邻区的水平形变场及应变率场，结合构造地质、地震目录等资料对渭河盆地及邻区的现今地壳形变及构造特征进行研究，并得到如下结论：（1）鄂尔多斯地块南缘西段和东段GPS形变场变化差异明显，六盘山-陇县-宝鸡断裂带形变场以挤压变形为主，渭河盆地中部西安-咸阳地区的形变场呈现EW向挤压、SN向拉张特征；（2）主应变率、剪应变率、面应变率变化明显的区域位于鄂尔多斯地块西南缘的六盘山-陇县-宝鸡断裂带、渭河盆地中部的长安-临潼断裂与渭南塬前断裂以及韩城断裂与双泉-临猗断裂附近；（3）未来需要警惕六盘山-陇县-宝鸡断裂带、长安-临潼断裂与渭南塬前断裂以及韩城断裂与双泉-临猗断裂附近的地震危险性。

Abstract:

Based on the GPS data of the Weihe Basin and its adjacent areas from 2009 to 2014 and the calculation method of continuous deformation field and strain field proposed by Shen, the horizontal deformation field and strain rate field of the Weihe Basin and its adjacent areas were obtained. Combined with the data of tectonic geology and seismic catalogue, the present crustal deformation and tectonic characteristics of Weihe Basin and its adjacent areas were studied in this paper, and the following conclusions were obtained:(1) The difference of GPS deformation field in the western and eastern parts of the southern margin of the Ordos block is obvious. The deformation field along the Liupanshan-Longxian-Baoji fault zone is dominated by compression, and the deformation field in the Xi'an-Xianyang area of the middle Weihe Basin is characterized by EW extrusion and SN extension; (2) The areas with significant changes in principal strain rate, shear strain rate, and surface strain rate are located along the Liupanshan-Longxian-Baoji fault zone in the southwestern margin of the Ordos block, the Chang'an-Lintong fault and Weinan fault in the central part of the Weihe Basin, and near the Hancheng fault and Shuangquan-Linyi fault; (3) In future, it is necessary to be alert to the seismic risks in the Liupanshan-Longxian-Baoji fault zone, Chang'an-Lintong fault and Weinan fault, as well as near the Hancheng fault and Shuangquan-Linyi fault.