鄂尔多斯块体南缘现今水平应变特征分析

Current Horizontal-strain Characteristics in the Southern Edge of Erdos Block

根据陕西省 2 0 0 1和 2 0 0 3年两期的GPS测站的观测资料 ,给出了鄂尔多斯块体南缘现今地壳水平应变场。结果表明 ,最大剪应变和面应变的高值区主要集中在该区中部和东部 ,尤其是在中部的咸阳、泾阳附近 ,东部的合阳、大荔、渭南一带以及西北部的陇县附近 ,主要受面收缩影响 ,分别形成了几个较为显著的应变高值区。等值线较密集并且应变梯度也较大 ,这些区域具备一定的孕震条件 。

According to the GPS data surveyed by Seismological Bureau of Shaanxi Province in Weihe Basin and its neighbouring Region from 2001 to 2003, the current crustal strain field data of the Erdos Block is got. Then, the following main results are proposed. Firstly, the high-value area of shear strain and the surface strain are predominant in the middle part as well as the east part of the research area, especially in Xianyang City and Jingyang City. In the east part of the research area,the surface tensile strain is predominant alongside Heyang, Dali, Weinan and Longxian County in northwest. As a result, several obvious high-value zones are formed. And the strain contour line seems compressive and the strain gradient is large. These zones have some kinds of seismogenic conditions and they are the potential epicenteral areas in future.