基于多地震序列震源机制解的盈江区域构造应力场研究

Study on tectonic stress field in Yingjiang area based on multi-focal mechanism solution sequence

文章搜集了盈江地区多个地震序列震源机制解共计162个,对从苏典断裂到大盈江断裂的区域进行了构造应力场反演。研究结果表明,该区域总的主压应力轴方向为NNE—SSW向。并从内在动力学演化的角度分析了2008年3月21日—2014年5月30日发生的6次震群活动,发现其存在明显的相互联系性。研究还发现,局部也出现应力场偏转的现象,苏典断裂南端的主压应力轴向北偏转角度变大,这可能与该区形成的三角凹陷有关。此外,本文还搜集到2016—2020年之间发生于盈江地区的1003个地震目录,通过分析发现昔马—盘龙山断裂到大盈江断裂之间的区域可能存在应力场闭锁,因此,加强该区域的危险性防范至关重要。

In this paper,a total of 162 focal mechanism solutions are collected from several focal mechanism solution sequences in Yingjiang area,and the tectonic stress field inversion is carried out from Sudian fault to Dayingjiang fault.The results show that the axial direction of the total principal compressive stress in this area is NNE—SSW.The six earthquake swarm activities from March 21,2008 to May 30,2014 were analyzed from the perspective of internal dynamic evolution,and it was found that there were obvious interrelationships among them.It is also found that the deflection of stress field occurs locally.The deflection angle of principal compressive stress axis at the southern end of Sudian fault becomes larger,which may be related to the triangular depression formed in this area.In addition,1003 earthquake catalogues occurred in Yingjiang area from 2016 to 2020 were collected in this paper.Through analysis,it is found that there is stress locking in the area between Xima-Panlongshan fault and Dayingjiang fault,so it is very important to strengthen the risk prevention in this area.