青藏高原东北缘及其周边地区现今构造应力场及地震活动性

Current Tectonic Stress Field and Seismic Activity in Northeastern Tibetan Plateau and Its Surrounding Areas

收集青藏高原东北缘及其周边地区371个震源机制解数据,对该区域进行1°×1°经纬度网格的构造应力场反演。结果表明,青藏高原东北缘内缘最大主压应力以NE向为主,外缘最大主压应力由西向东呈现出顺时针旋转的特征,即最大主压应力轴由西段近NNE向转为中段NE向,再转为东段NWW向。从不同深度对青藏高原东北缘及其周边地区进行2°×2°经纬度网格的构造应力场反演。结果显示,地壳上下部分断层体系存在巨大的变化差异,产生这种差异的原因可能与地壳的挤压增厚有关。

We collect 371 focal mechanism solutions in northeastern Tibetan plateau and its surrounding areas,and carry out a grid 1°×1°tectonic stress field inversion.The results show that the maximum principal compressive stress on the inner edge of the northeastern Tibetan plateau is mainly NE,and the maximum principal compressive stress on the outer edge shows the characteristics of clockwise rotation from west to east,that is,the axis of the maximum principal compressive stress changes from near NNE in the west to NE in the middle,and then from NE in the middle to NWW in the east.From the perspective of different depths,the northeastern Tibetan plateau is calculated by 2°×2°stress field inversion.The results show that there is a huge difference in the fault system between the upper and lower parts of the crust,and the reason for this difference may be related to the compressive thickening of the crust.