利用EGM2008地球重力场模型研究川西地区水平构造应力场

利用EGM2008地球重力场模型数据计算川西地区的水平构造应力场。结果显示,采用重力场数据可以快速获得水平构造应力场图像;龙门山断裂带及鲜水河-安宁河断裂带水平构造应力聚集程度较高,构造应力值较大,反映出这些地区地质构造运动活跃;水平构造应力方向从巴颜喀拉块体到华南地块再到川滇块体呈现顺时针方向旋转;构造应力场随着深度的增加呈逐渐减小的趋势,地震活动频率也相应降低;构造应力场等值线密集区构造运动活跃、地震活动频发,表明地震活动与构造应力聚集分布存在一定的对应关系。

Research on Horizontal Tectonic Stress Field Based on EGM2008 in Western Sichuan

We studied the method of computing the horizontal tectonic stress field by the earth gravity field, and then the horizontal tectonic stress field in western Sichuan is computed with the EGM2008. The results show that we can quickly obtain the tectonic stress field using gravity field data. The horizontal tectonic of the Longmenshan and Xianshuihe-Anninghe fault zones is greater, and the accumulation degree is higher than any other area, which reflects that tectonic movement is more active in these areas. The horizontal tectonic stress from the Bayanhar block to the southern China block to the Sichuan-Yunnan block shows clockwise rotation. In the Bayanhar block and southern China block boundary, the strong stop of Sichuan basin in the south China block results in the formation of Longmenshan foreland thrust zone. The tectonic stress field gradually decreases with the increase of depth, and the frequency of seismic activity decreases accordingly. The tectonic stress field is densely distributed with active tectonic activity and frequent seismic activity, which indicates that there is a corresponding relationship between seismic activity and tectonic stress accumulation.