论文部分内容阅读
大理地区之所以成为一个地震活跃区,与该区受一组北东向活断层的影响有关。为了进一步探讨本区应力场的特征和这组断层的影响,笔者用有限单元法对该区进行了模拟计算和力学分析。结果表明;作用到该区区域应力的主方向为北15°—20°西。区内各点,特别是断层带内外之间,主应力的方向变化很大。剪应力平均值大的地区,多数和地震多发地点相一致。北东和近东西向两组断层于该区的存在对本地震带的形成有重要作用。同时表明,除现在已知的地震多发点外,鹤庆、乔后至漾濞、巍山西南一带也应注意。
The reason why the Dali region became a seismic active area is related to the influence of a group of NE-trending active faults in this area. In order to further explore the characteristics of the stress field in this area and the influence of this group of faults, the author carried out the simulation and mechanics analysis of this area by finite element method. The results show that the main direction of stress acting on this area is north 15 ° -20 ° west. Various points in the area, especially the fault zone between the inside and outside, the main stress direction changes greatly. Most of the areas with large average shear stress are consistent with the sites with frequent earthquakes. The existence of two sets of faults in the NE and NEWS plays an important role in the formation of this earthquake zone. At the same time, in addition to the now known earthquakes, Heqing, Qiaohou to Yangbi, Weishan southwest area should also be noted.