中强震对地壳应力场的影响——以盈江地区5次中强震为例  

The influence of moderate earthquakes on the crustal stress field inferred from 5 moderate earthquakes in Yingjiang area

作　　者：盛书中 万永革[2] 胡晓辉 宫猛 张苏祥 SHENG ShuZhong;WAN YongGe;HU XiaoHui;GONG Meng;ZHANG SuXiang(School of Geophysics and Measurement-control Technology,East China University of Technology,Nanchang 330013,China;Institute of Disaster Prevention,Sanhe Hebei 065201,China;University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]东华理工大学地球物理与测控技术学院,南昌330013 [2]防灾科技学院,河北三河065201 [3]中国科学技术大学,合肥230026

出　　处：《地球物理学报》2022年第6期2063-2073,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41704053,41674055,42174074);东华理工大学博士科研启动基金(DHBK2019084)共同资助。

摘　　要：为了研究中强震对震源区应力场的影响,本研究以盈江地区2008—2014年间发生的5次中强震为例,深入研究这5次中强震对盈江地区地壳应力场的时空影响.为了探究中强震对应力场的时空影响,我们对盈江地区地壳应力场进行了以下研究:根据5次中强震发生时间,分时段反演应力场以考察应力场在时间上是否存在变化;根据震源机制解的空间分布,将研究区分为南部和北部反演应力场,以确定应力场是否存在空间差异;随机抽取震源机制解反演应力场以便确定应力场是否存在时空差异.研究结果表明:(1)5次中强震对盈江地区应力场产生的扰动较小,没有引起盈江地区应力场在时间上的显著变化;(2)在研究时段内,盈江地区地壳应力场在时空上可以视为均匀应力场;(3)盈江地区的地壳应力场为走滑型,最大主应力轴呈NNE-SSW向,最小主应力轴呈SEE-NWW向,最大和最小主应力轴倾角近水平,中间主应力轴倾角近直立.To study the influence of moderate earthquake on the stress field in the seismic source area,5 moderate earthquakes that occurred in the Yingjiang area from 2008 to 2014 were analyzed.We analyzed several aspects of the crustal stress field in the Yingjiang area to investigate the spatiotemporal impact of those moderate earthquakes on the crustal stress.According to the earthquake occurrence time of the 5 moderate earthquakes,the stress field was inverted within different time periods to investigate the potential temporal change of the stress field.The stress field is inverted separately by using focal mechanism from the southern and northern part to investigate the spatial difference in the stress field.The robustness of temporal and spatial variations in the stress field is examined by random sampling.The results are summarized as follows.First,the 5 moderate earthquakes caused minor disturbances to the stress field in the Yingjiang area,and did not cause significant temporal variations to the regional stress field;Second,during the study period,the crustal stress field in Yingjiang area can be regarded as a spatiotemporal uniform stress field;Third,the crustal stress field in Yingjiang area is in a strike-slip regime,for which the maximum compressive principal stress axis is in the NNE-SSW direction with subhorizontal plunge,the minimum compressive principal stress axis is in the SEE-NWW direction with subhorizontal plunge,and the intermediate principal stress axis is approximately vertical.

关 键 词：地壳应力场 应力偏转 盈江地区 震源机制解 中强震 

分 类 号：P315[天文地球—地震学]