唐山地区地震成因初探—以丰南2010年M4.1和2019年M4.5地震序列为例  

Discussion on the seismogenesis of Tangshan area:take the sequence of Fengnan M 4.1 in 2010 and M 4.5 in 2019 as an example

作　　者：李赫[1] 董一兵[2,3] 王熠熙 孔军[4] 吴博洋 彭钊 郑世禄 彭研枫 李金霞 LI He;DONG Yi-bing;WANG Yi-xi;KONG Jun;WU Bo-yang;PENG Zhao;ZHENG Shi-lu;PENG Yan-feng;LI Jin-xia(Earthquake Administration of Tianjin Municipality,Tianjin 300201,China;Hebei University of Economics and Business,Shijiazhuang 050061,China;State Key Laboratory of Geodesy and Earth’s Dynamics,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430077,China;Guizhou Earthquake Agency,Guiyang 550001,China)

机构地区：[1]天津市地震局,天津300201 [2]河北经贸大学,石家庄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430077 [4]贵州省地震局,贵阳550001

出　　处：《地球物理学进展》2020年第4期1276-1283,共8页Progress in Geophysics

基　　金：中国地震局地震科技星火计划项目(XH19005Y);中国地震局地震科技星火计划项目(XH20003Y);中国地震局地震科技星火计划项目(XH19004YSX);中国地震局三结合课题(3JH-202001004)联合资助;河北经贸大学科研基金项目(2018QZ11,2018QY08);河北省教育厅项目(2016GJJG085)。

摘　　要：自1976年唐山M 7.8地震之后,唐山地区中小地震不为鲜见.在唐山市丰南区,相继发生了2010年M 4.1地震和2019年M 4.5地震,两者相距仅18 km左右.为了探究它们的发震构造以及与唐山M 7.8地震之间的成因关系,从而窥见该地区的地震成因.本文基于首都圈数字地震台网的地震资料,利用CAP方法获取了这两次地震的震源机制和矩心深度,并利用近震sPL深度震相对矩心深度进行准确测定,结合双差定位得到的地震序列位置,对它们的发震机理进行了探讨.结果显示:(1)丰南M 4.1地震震源机制解节面Ⅰ为60°/85°/163°(走向/倾角/滑动角),节面Ⅱ为151°/75°/6°,震源错动类型显示为走滑特征;震源深度为15 km;地震序列震中沿NE向分布,短轴剖面揭示倾向SE、倾角陡立,推测节面Ⅰ为发震断层面,结合深地震反射剖面资料,其发震构造为唐山地壳深断裂,与唐山M 7.8地震发震构造相同.(2)丰南M 4.5地震震源机制解节面Ⅰ为254°/73°/-120°,节面Ⅱ为137°/34°/-31°,震源性质拉张兼走滑;震源深度为14.5 km;地震序列震中沿NEE向分布,短轴剖面显示为倾向NW、倾角陡立,推测节面Ⅰ为发震断层面;结合地震测深剖面资料,发震构造应该是宁河昌黎深断裂.(3)基于两次地震的震源参数结果,结合渤海湾盆地动力条件、发震断裂的运动学特征以及地壳精细结构等资料,本文认为唐山丰南M 4.1和M 4.5地震以及该地区中小地震活动频发与该地区地壳深、浅部叠加的构造系统密切相关.Since the 1976 Tangshan M 7.8 earthquake,tangshan area small earthquakes are not rare.In fengnan district,tangshan city,the M 4.1 earthquake in 2010 and the M 4.5 earthquake in 2019 occurred successively,with a distance of only about 18 km.To explore their seismogenic structure and the relationship between the cause of the Tangshan M 7.8 earthquake,to see the area of earthquake prediction,this article,based on the seismic data of digital seismic network in the capital circle,with CAP method to obtain the twice the focal mechanism of earthquake and centroid depth,and use the near earthquake sPL depth relatively accurately measuring centroid depth,combined with the double difference location positioning of the earthquake sequence,the seismogenic mechanism of them are discussed in this paper.Results show that:(1)the abundant south M 4.1 earthquake focal mechanism solutions of nodal planeⅠis 60°/85°/163°(strike/dip/rake angle),section planeⅡfor 151°/75°/6°,focal rupture type display is a strike-slip feature;The focal depth was 15 km;Earthquake sequence along the NE to the epicenter distribution of short vertical shaft section reveals tendency SE,dip,speculated that nodal planeⅠfor seismogenic fault surface,combined with the data of deep seismic reflection profile,the seismogenic structure of tangshan crustal deep fracture,the same as the tangshan M 7.8 earthquake seismogenic structure.(2)abundant south M 4.5 section planeⅠearthquake focal mechanism solutions of 254°/73°/-120°,nodal planeⅡto 137°/34°/-31°,the source properties tensile and strike-slip;The focal depth was 14.5 km.The epicenter distribution along the NEE to earthquake sequence,short axis vertical section shows for tendency NW,dip,speculated that nodal planeⅠseismogenic fault plane;Combined with seismic sounding profile data,the seismogenic structure should be the changli deep fault of ninghe river.(3)based on the source parameter results of the two earthquakes,combined with the dynamic conditions of the bohai bay basin,the kinemat

关 键 词：唐山丰南M 4.1和M 4.5地震 唐山地壳深断裂 宁河昌黎深断裂 发震构造 

分 类 号：P315[天文地球—地震学]