2023年广东河源M≥4地震序列震源参数及应力触发  

Source parameters and stress triggering of 2023 M≥4 earthquakes sequence in Heyuan,Guangdong

作　　者：黄润青 邓阳凡[1] 陈瑛 熊成 张周 HUANG RunQing;DENG YangFan;CHEN Ying;XIONG Cheng;ZHANG Zhou(State Key Laboratory of Deep Earth Processes and Resources,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Guangdong Earthquake Agency,Guangzhou 510070,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai Guangdong 519082,China)

机构地区：[1]中国科学院广州地球化学研究所,深地过程与战略矿产资源全国重点实验室,广州510640 [2]中国科学院大学地球与行星科学学院,北京100049 [3]广东省地震局,广州510070 [4]南方海洋科学与工程广东省实验室(珠海),广东珠海519082

出　　处：《地球物理学报》2025年第3期956-969,共14页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42204071,42322401);广州市科技计划资助项目(202201010453)资助。

摘　　要：广东省河源市分别于2023年2月11日和3月8日发生了M4.0地震和M4.3地震,这两次地震均位于新丰江库区内,并在周围地区产生了较强的震感.新丰江水库是世界上仅有的四座发生过6级以上地震的水库之一.自1970年以来,新丰江库区发生的4级以上地震仅有16次,2023年库区在两个月内连续发生两次4级以上地震,表明新丰江库区仍具有发生4级或更大地震的可能性,而2023年这两次地震的发震构造及地下应力变化特征目前仍不清楚.本研究基于2023年2月1日至3月12日期间的连续地震波形资料,利用机器学习的震相拾取技术(EQTransformer)进行微震识别及震相拾取,共识别出1220个地震事件,是原先地震目录地震数的2倍;利用双差定位方法(HypoDD)对该地震目录进行地震精定位,结果显示新丰江库区的地震空间分布较为集中,两次M≥4地震的地震序列在水平面上呈NW-SE向展布,震源深度分布于5~15 km范围内,震中随深度的分布呈大角度向深部延伸;通过gCAP波形反演计算了这两次M≥4地震的震源机制解,并反演了构造应力场.反演结果表明,2月11日地震发生于一条NEE走向、倾向SE的左旋走滑隐伏断裂,3月8日地震发生于一条NW走向、倾向SW的右旋走滑隐伏断裂;利用AutoCoulomb程序包计算了两次地震引起的库仑应力变化,结果表明M4.0地震对后续M4.3地震具有一定的触发作用.本研究为进一步认识新丰江水库的发震构造及地下应力变化提供了可靠的参考依据.Two magnitude larger than 4 earthquakes(M4.0,M4.3)occurred in Heyuan City,Guangdong Province on February 11 and March 8,2023 respectively.These two earthquakes were both located in the Xinfengjiang(XFJ)Reservoir area and widely felt in the surrounding areas.The XFJ Reservoir is one of four reservoirs in the world that has occurred M≥6 earthquakes.Since 1970,there have been only 16 M≥4 earthquakes in the XFJ Reservoir area.However,two M≥4 earthquakes occurred in this area within two months in 2023,indicating that the XFJ Reservoir area still has the possibility of earthquake with M≥4.The seismogenic structure and stress change characteristics of these two earthquakes in 2023 remain unclear.In this study,we performed a microearthquake detection and seismic phase picking using continuous waveform data from February 1 to March 12,2023,based on machine learning-based seismic phase picking technique(EQTransformer).1220 earthquakes were detected,about two times the number of events listed in the original catalog.We then applied a double-difference earthquake location algorithm(HypoDD)to relocate earthquakes in the catalog.Relocation results show that earthquake sequence of the two M≥4 was concentrated at depth of 5~15 km with the epicenter extends to the deep at a large angle along the depth direction,and horizontally distributed in the NW-SE direction.The gCAP method was used to calculate the focal mechanism of two M≥4 earthquakes,and tectonic stress field was inversed.The results show,the February 11 earthquake occurred on an NEE trending left-lateral strike-slip hidden fault,with dip direction towards SE,while the March 8 earthquake occurred on an NW trending right-lateral strike-slip hidden fault,with dip direction towards SW.Moreover,Coulomb stress changes were calculated by AutoCoulomb program,indicates that Coulomb stress from the M4.0 earthquake may contribute to the triggering of the subsequent M4.3 earthquake to some extent.Our results provide reliable source for further understanding of the seismo

关 键 词：水库诱发地震 发震构造 震源机制 构造应力场 库仑应力变化 

分 类 号：P315[天文地球—地震学]