渭河断裂西安段的展布及其结构特征  

Distribution and structural characteristics of the Xi'an section of the Weihe fault

作　　者：师亚芹[1] 冯希杰[1] 戴王强[1] 任隽[1] 李晓妮[1] 韩恒悦[1] 

机构地区：[1]陕西省地震局,中国西安710068

出　　处：《地震学报》2008年第6期634-647,共14页Acta Seismologica Sinica

基　　金：The Project from State Development and Reform Commission (20041138);Joint Seismological Science Foundation of China (A07109).

摘　　要：地震深反射、高分辨率折射和浅层人工地震探测结果表明,渭河北岸断裂由两条断层组成:一条为窑店—张家湾断层,另一条为船张—咀头断层.窑店—张家湾断层从陈家沟,经窑店镇、前排村、庇李村、吴家村、张家湾到贾家滩,长约22 km,基本呈东西走向;船张—咀头断层从船张,经马北到咀头,长约15 km,近东西走向.渭河断裂为基底和上地壳断裂,错断了T_Q、T_N、T_E和T_g反射层,深约15 km.在深部渭河断裂与次级断层形成"Y"字型构造或同向低角度相交.渭河断裂为铲形正断层.该断裂深度在1000 m以浅,具有明显的逆牵引正断层和正牵引正断层的结构特性,并具有同生沉积的特点.渭河断裂是控制盆地沉积的断裂之一,是西安凹陷与咸阳凸起的分界断裂.该断裂从西向东深度逐渐减小,深部在渭河、泾河和灞河三河交汇区与临潼—长安断裂相交,浅部与渭南—泾阳断裂相连.地震探测结果同时表明,渭河南岸断裂不存在.Results of seismic deep reflection, high resolution refraction and shallow artificial seismic exploration indicate that the fault on the northern bank of the Weihe river is composed of two branches： one is the Yaodian-Zhangjiawan fault and the other is the Chuanzhang-Zuitou fault. The 22 km long Yaodian- Zhangjiawan fault of E-W strike starts from Chenjiagou, via Yaodian town, Qianpai village, Bili village, Wujia town and Zhangjiawan, to Jiajiatan. The 15 km long Chuanzhang-Zuitou fault striking near E-W starts from Chuanzhang, via Mabei, to Zuitou. The Weihe fault is a basement and upper crust fault and the reflection layers of TQ, TN, TE and Tg are ruptured at depth of about 15 km. In deep part the Weihe fault and the secondary fault iorm a Y-snaped structure or a synthetic low angle intersection. The Weihe fault is a listric normal fault, which has obvious structural characteristics of a reverse-drag normal fault and a normal-drag normal fault within a depth of 1000 m, and also has the characteristics of syngenetie sediment. The Weihe fault is one of the faults which control the basin sediment, and is the boundary fault between Xi＇ an depression and Xianyang salient. The fault depth decreases gradually from west to east. Its deep part intersects with the Lintong-Chang＇an fault at the intersection of Weihe River, Jing River and Bahe River, and its shallow part connects with the Weinan-Jingyang fault. The seismic exploration result indicates that no fault exists on southern bank of the Weihe River.

关 键 词：渭河断裂 地震深反射 高分辨率折射 浅层人工地震 逆牵引正断层 正牵引正断层 同生沉积 

分 类 号：P315.2[天文地球—地震学]