2023-08-23辽宁普兰店M 4.6地震震源参数测定及发震构造初判  

Determination of Source Parameters of the M 4.6 Earthquake in Pulandian,Liaoning Province on August 23,2023,and Preliminary Judgement of Its Seismogenic Structure

作　　者：戴盈磊[1] 张文静 杨晓东[1] 索锐[1] 王承伟[1] DAI Yinglei;ZHANG Wenjing;YANG Xiaodong;SUO Rui;WANG Chengwei(Liaoning Earthquake Agency,44 North-Huanghe Street,Shenyang 110031,China)

机构地区：[1]辽宁省地震局,沈阳市110031

出　　处：《大地测量与地球动力学》2025年第1期48-54,59,共8页Journal of Geodesy and Geodynamics

基　　金：辽宁省地震局预研孵化基金(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(XH24009YA)。

摘　　要：2023-08-2318:19辽宁省大连市普兰店区发生M 4.6地震,为准确描述本次地震的震源特征,探讨其孕育和发震机理,本文通过测定地震的震源深度,反演震源机制、矩张量及质心深度,给出震源机制中心解;同时分析震源机制与构造应力场的关系,根据小震重定位结果对发震断层面进行拟合,初步确定了本次地震的发震断层。结果表明,普兰店M 4.6地震初始破裂深度为12.0 km,震源机制解参数为节面Ⅰ走向50°,倾伏角75°,滑动角-169°;节面Ⅱ走向317°,倾伏角80°,滑动角-15°,矩震级M W4.8,最优质心深度12 km;地震矩M_(0)为1.796×10^(16)Nm,矩张量解M_(rr)、M_(tt)、M_(pp)、M_(rt)、M_(rp)、M_(tp)分别为-0.004、0.946、-0.942、0.017、-0.305、-0.125;中心解参数为节面Ⅰ走向47.03°,倾伏角79.04°,滑动角-168.15°;节面Ⅱ走向314.75°,倾伏角78.37°,滑动角-11.19°。构造应力场作用在中心解节面Ⅰ上的相对剪应力为0.877,相对正应力为-0.544;投影于节面Ⅱ上的相对剪应力为0.911,相对正应力为0.161。拟合的断层面走向148.91°,倾伏角89.85°,其在构造应力体系下的滑动角为26.47°。综合分析认为,普兰店M 4.6地震发生在NW向普兰店-长海构造带,是沿应力场最优节面以左旋走滑为错动方式的天然地震。On August 23,2023,a M 4.6 earthquake hit the Pulandian,Liaoning province.To describe the source characteristics of this earthquake,we explore its incubation and seismogenic mechanisms.In this paper we determined the focal depth of the Pulandian M 4.6 earthquake,and calculate the focal mechanism solution,moment tensor solution and centroid depth of the earthquake,obtain the center of focal mechanisms of the earthquake.In the same,we analyze the relationship between focal mechanism and tectonic stress field,and fit the fault plane according to the results of small earthquake relocation.We preliminarily determine the seismogenic fault plane of this earthquake.The results show that the initial rupture depth of the Pulandian M 4.6 earthquake is 12.0 km.The focal mechanism solution mechanism solution is strike:50°,dip:75°and rake:-169°for nodal planeⅠ,strike:317°,dip:80°and rake:-15°for nodal planeⅡ,the moment magnitude is M W4.8,while the centroid is 12 km.The seismic moment M_(0)is 1.796×10^(16)Nm,the moment tensor solution is M_(rr):-0.004,M_(tt):0.946,M_(pp):-0.942,M_(rt):0.017,M_(rp):-0.305,M_(tp):-0.125.The center of focal mechanisms solution is strike:47.03°,dip:79.04°and rake:-168.15°for nodal planeⅠ,strike:314.75°,dip:78.37°and rake:-11.19°for nodal planeⅡ.The relative shear stress and relative normal stress generated by the tectonic stress field acting on the nodal planeⅠare 0.877 and-0.544;on nodal planeⅡthey are 0.911 and 0.161.The fitted seismogenic fault plane is strike:148.91°,dip:89.85°and rake:26.47°.The analysis shows that the Pulandian M 4.6 earthquake occurred on the Pulandian-Changhai NW tectonic belt.It is a natural earthquake that after stress accumulation occurs along the optimal nodal plane of the stress field and takes left-lateral strike-slip as the dislocation mode.

关 键 词：普兰店M 4.6地震 初至P震相定位法 gCAP 震源机制 构造应力场 

分 类 号：P315[天文地球—地震学]