铅垂断层向错引起的地表重力变化  

A Gravity Changes Theory of Vertical Fault Disclinations

作　　者：段虎荣[1] 杨凡[1] 

机构地区：[1]西安科技大学测绘科学与技术学院,西安市雁塔路58号710054

出　　处：《大地测量与地球动力学》2015年第4期627-631,共5页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(41304013;41374028);陕西省教育厅自然科学项目(12JK0798;2010JK670);西安科技大学博士基金(2014QDJ054)

摘　　要：利用直立长方体组合模型以及坐标旋转理论,对铅垂断层向错引起的重力变化进行数值模拟,分别计算深度为1、5、10km的铅垂断层在单一方向上、两个方向上向错引起的地面重力变化。结果表明,当断层在单一方向产生向错时,以左端点为基点的W1、W2向错引起的地面重力变化场均呈现以断层为轴线的对称分布;以中点为基点的W3向错引起的地面重力变化场构成四象限反对称分布。当断层在两个方向上同时产生向错时,以左端点为基点的W1W2向错引起的地面重力变化场呈现以断层为轴线的对称分布,整体显示W2向错起主导作用;以中点为基点的W2W3向错引起的地面重力变化场呈现非对称分布,整体也显示出W2向错起主导作用,断层附近的扭错现象为W3向错的作用。随着断层深度的增加,断层向错引起的地面重力变化值递减,但影响范围逐渐扩大。Simulated fault parameter values are adopted to deduce the earth surface gravity changes with the combination model of vertical rectangular and the coordinate rotation theory. Numerical sim- ulated experiments of gravity change distribution are conducted for the activities of the vertical fault disclination in a single direction and in two directions, respectively, at depths of 1 km, 5 km and 10 km. The conclusions show that the gravitational variation field shows symmetrical distribution when the vertical fault occurs with a disclination of W1 or W2 pattern based on the left point of the fault in a single direction. In addition, it appears that four quadrants show an antisymmetric distribution when a vertical fault occurs with a disclination of W3 pattern based on the midpoint of the fault. The gravitational variations field shows symmetrical distribution when the vertical fault occurs with a disclination of W1W2 pattern based on the left point of the fault. Moreover, the W2 pattern plays an important role. Gravitational variations field presents a symmetrical distribution when the vertical fault occurs with a disclination of W2W3 pattern based on the midpoint of the fault, with an obvious twisting phe- nomenon that is attributed to the disclination of W3 pattern in the fault vicinity. Overall, it also shows that the W2 pattern plays an important role. The earth surface gravity change is decreasing progres- sively when the depth of faults is increasing. However the region influenced by the vertical fault disclination is extending.

关 键 词：向错 铅垂断层 重力变化 直立长方体组合模型 

分 类 号：P315.7[天文地球—地震学]