摘要
基于新疆测震台网的宽频带观测记录,利用CAP方法反演2017年8月9日精河MS6.6地震及早期14次MS≥3.0余震的震源机制解,应用MSATSI软件反演震源处应力场。结果表明,此次地震为逆断型,结合震源机制解和附近地质构造背景,推断此次地震的发震构造为库松木契克山前断裂的东段,节面Ⅰ走向89°,倾角43°,滑动角91°为发震断层面。14次余震中有11次为逆断型地震,1次为正断型地震,2次为走滑型地震。P轴在近NS向有明显的优势分布且倾角较小,T轴倾角较陡,表明震源处主要以近NS方向的水平挤压作用为主。反演得到的震源深度分布在12~21km,深度优势分布为15~20km,略小于主震的震源深度21km。应力场的反演结果与震源机制参数统计结果一致,均显示震源处主要受近NS向水平应力场控制。
On August 9,2017,an M S6.6 earthquake occurred in Jinghe County,Xinjiang,China,and its epicenter was at 44.27°N,82.89°E.Based on the broadband waveform recorded by the Xinjiang Seismic Network,we used the cutandpaste method to invert the focal mechanism solutions of the main shock and 14 M S≥ 3 aftershocks.Additionally,the stress field in the source area was inverted using MSATSI software.According to the focal mechanism solutions and surrounding geological data,we infer that the seismogenic fault is the eastern segment of the Kusongmuqike piedmont fault,and we identified nodal plane I with a strike of 89°,dip of 43°,and rake of 91°as seismogenic fault plane of the main shock.Of the 14 aftershocks,11 were the thrust type,one was a normal faulting type,and two were the strikeslip type.The P axis is concentrated in the near NS direction and has a small inclination angle,whereas the inclination angle of the T axis is large.This indicates that the stress field of the source region is characterized by a nearly NS horizontal compression.The focal depths of the M S6.6 earthquake sequence ranged from 12 to 21 km,but were concentrated in the range of 15-20 km;thus,they were slightly shallower than the focal depth (21 km) of the main shock.The inversion result of the stress field in the source area accords with the statistical results of the focal mechanism parameters;thus,both indicate that the source area is mainly controlled by the horizontal stress field in the near NS direction.
作者
李艳永
王成虎
LI Yanyong;WANG Chenghu(Earthquake Agency of Xinjiang Uygur Autonomous Region,Urumqi 830011,Xinjiang,China;Institute ofCrustal Dynamics,China Earthquake Agency,Beijing 100085,China)
出处
《地震工程学报》
CSCD
北大核心
2019年第5期1280-1289,共10页
China Earthquake Engineering Journal
基金
国家自然科学基金(41574088)
新疆地震科学基金(201906)
新疆精河6.6级地震余震重新定位与震源破裂过程(60177904)
新疆维吾尔自治区自然科学基金面上项目(2016D01A061)
中国局三结合课题(3JH-201901016)
