2021年滦州M_(S)4.3地震和2015年昌黎M_(S)4.2地震震源参数及构造意义研究  

Research on the Source Parameters and Tectonic Significance of the 2021 Luanzhou M_(S)4.3 Earthquake and the 2015 Changli M_(S)4.2 Earthquake

作　　者：李赫[1] 董一兵[2,3] 王熠熙 LI He;DONG Yibing;WANG Yixi(Tianjin Earthquake Agency,19 Youyi Road,Tianjin 300201,China;School of Information Technology,Hebei University of Economics and Business,47 Xuefu Road,Shijiazhuang 050061,China;State Key Laboratory of Geodesy and Earth’s Dynamics,Innovation Academy for Precision Measurement Science and Technology,CAS,340 Xudong Street,Wuhan 430077,China)

机构地区：[1]天津市地震局,天津市300201 [2]河北经贸大学信息技术学院,石家庄市050061 [3]中国科学院精密测量科学与技术创新研究院大地测量与地球动力学国家重点实验室,武汉市430077

出　　处：《大地测量与地球动力学》2022年第12期1281-1287,共7页Journal of Geodesy and Geodynamics

基　　金：天津市地震局科研项目(Zd202108,Zd202204);中国地震局地震科技星火计划(XH20003Y);中国地震局“三结合”课题(3JH-202201040);河北经贸大学科学研究与发展计划(2021ZD06);河北省高等教育教学改革研究与实践项目(2021GJJG175);河北经贸大学教学研究项目(2021JYQ05)。

摘　　要：基于京津冀地震台网观测资料,利用CAP方法反演滦州M_(S)4.3地震、昌黎M_(S)4.2地震及其M_(S)3.3余震的震源机制,并利用近震深度震相获得更为准确的震源深度,结合双差定位法获得2个地震序列的震源分布结果,对发震构造及成因关联开展分析研究。结果显示:1)滦州M_(S)4.3地震的节面Ⅰ走向、倾角、滑动角分别为211°、85°、168°,节面Ⅱ分别为302°、78°、5°,震源错动类型为走滑型,震源深度为8 km,地震序列的震源分布呈NNE向,短轴剖面显示断层面倾角近垂直,认为其发震断层面为节面Ⅰ;昌黎M_(S)4.2地震及M_(S)3.3余震的节面Ⅰ分别为189°、68°、161°及190°、61°、170°,节面Ⅱ分别为286°、72°、23°及285°、81°、29°,震源错动类型同为走滑型,震源深度为10.5 km,地震序列的震源分布呈NNE向,短轴剖面显示断层面倾角近垂直,认为其发震断层面为节面Ⅰ;2)基于滦州M_(S)4.3地震、昌黎M_(S)4.2地震及滦州M_(S)7.1地震的震源参数结果,结合区域地质构造等资料分析认为,3次地震的发震构造不是上地壳先存断裂,而可能与震源区的深部构造背景密切相关,即壳内包体现象是孕育这些地震的共同基础。In order to explore their seismogenic structures and their genesis,based on the observation data of the Beijing-Tianjin-Hebei Seismic Network,we use the CAP method to invert the focal mechanism solutions and centroid depths of the Luanzhou M_(S)4.3 earthquake,the Changli M_(S)4.2 earthquake and their M_(S)3.3 aftershocks.We use the local seismic depth phase sPL to obtain more accurate moments.According to the depth of the center,combined with the double-difference positioning method,we obtain the source distribution results of the two sequences,and analyze the seismogenic structure and genetic correlation.The results show that:1)The strike,dip and slip angles of nodal planeⅠof the Luanzhou M_(S)4.3 earthquake are 211°,85°,and 168°,respectively,and nodal planeⅡare 302°,78°,and 5°,respectively.It is a strike-slip type,the focal depth is 8 km,the focal distribution of the earthquake sequence is NNE,and the short-axis section seismic distribution shows a near-vertical dip and a high dip angle.It is considered that the seismogenic fault plane is a nodal planeⅠ.The nodal planeⅠof the aftershocks are 189°,68°,161°and 190°,61°,170°respectively;the nodal planeⅡare 286°,72°,23°and 285°,81°,29°,respectively.The focal dislocation type is both strike-slip type,the focal depth is 10.5 km,the focal distribution of the earthquake sequence is NNE direction,the short-axis section shows a near-vertical dip,high dip angle,and the seismogenic fault plane is considered to be the nodal planeⅠ.2)Based on the source parameters of the Luanzhou M_(S)4.3 earthquake,the Changli M_(S)4.2 earthquake and the Luanzhou M_(S)7.1 earthquake,combined with regional geological structural data,we believe that the seismogenic structures of these three earthquakes are not preexisting in the shallow crust.It may be related to the low-velocity layer in the crust in the source area,and the interlaced inclusions of high-velocity and low-velocity bodies in the crust are the common basis for these earthquakes.

关 键 词：滦州M_(S)4.3地震 昌黎M_(S)4.2地震 滦州M_(S)7.1地震 发震构造 低速层 

分 类 号：P315[天文地球—地震学] P313[天文地球—固体地球物理学]