基于构造应力场的震源机制解发震断层面识别——以辽宁海城、营口及周边地区为例  

Identification of Seismogenic Fault Plane of Focal Mechanism Solutions Based on Tectonic Stress Fields:A Case study of Haicheng and Yingkou of Liaoning Province and Their Surrounding Areas

作　　者：戴盈磊[1] 李子昊 李林侗[1] 刘霖婷 侯作亮[1] DAI Yinglei;LI Zihao;LI Lintong;LIU Linting;HOU Zuoliang(Liaoning Earthquake Agency,Shenyang 110034,China)

机构地区：[1]辽宁省地震局,沈阳110034

出　　处：《华南地震》2024年第4期11-20,共10页South China Journal of Seismology

基　　金：辽宁省地震局预研孵化基金项目(LZ2022001);中国地震局地震应急青年重点任务(CEA_EDEM-20240203);中国地震局地震科技星火计划项目(XH24009YA)联合资助。

摘　　要：为探讨基于构造应力场的震源机制解发震断层面识别方法在辽宁地区的适用性。采用P波初动方法计算并收集了辽宁地区253个震源机制解。参照震源机制水平应变花面应变对其进行分类。在反演震源区构造应力场的同时,给出判定的震源机制解发震断层面。结果表明:辽宁地区的地震多为走滑型和正断型。构造应力场最大主应力优势分布方位为NEE向,倾伏角多为水平或近直立;中间主应力方位离散,倾伏角较陡;最小主应力以NNW向为主,倾伏角较小;总体上属于张应力占主导的走滑应力体系。识别出195个震源机制解发震断层面符合主要发震控震构造特征及安德森断层形成力学理论。对于中强地震准确性显著,对于小震也能保证一定的可靠性。证明在辽宁地区应用该方法是可行的。In order to explore the applicability of the identification method of seismogenic fault plane of focal mechanism solutions based on the tectonic stress field in Liaoning area,the P-wave first motion method was used to calculate and collect 253 focal mechanism solutions in Liaoning area.They were classified according to the areal strain of the horizontal strain rosette of the focal mechanism.While inverting the tectonic stress field in the source area,the determined seismogenic fault plane of focal mechanism solutions was given.The results show that earthquakes in Liaoning area are mostly strike-slip and normal faults.The dominant distribution direction of the maximum principal stress in the tectonic stress field is NEE,and the dip angle is mostly horizontal or nearly vertical.The orientation of intermediate principal stress is discrete,and the dip angle is steep.The minimum principal stress is mainly in the NNW direction,and the dip angle is small.In general,it belongs to a strike-slip stress system dominated by tensile stress.The identified 195 seismogenic fault planes of focal mechanism solutions are consistent with the characteristics of main seismic control structures and Anderson fault theory.The accuracy is remarkable for intermediate and strong earthquakes,and there is also certain reliability for small earthquakes.This paper proves that the application of this method in Liaoning is feasible.

关 键 词：震源机制解 构造应力场 断层不稳定系数 发震断层 辽宁地区 

分 类 号：P315.7[天文地球—地震学]