摘要
基于云南地震台网和腾冲火山台网的宽频带地震波形资料和震相报告文件以及川滇地区高分辨率公共速度模型2.0版,采用结合波形互相关技术的双差相对定位法对2023年云南芒市M_(L)4.0震群序列中442次地震进行重定位,利用CAP方法反演了地震序列中M_(L)≥3.5地震震源机制解,研究了芒市M_(L)4.0震群序列的发震机理,探讨该震群是前震序列还是普通震群。双差定位法获得了363次地震的精定位结果,震中走向呈NE向,地震序列呈三角形形态分布。CAP波形反演M_(L)4.0地震最佳双力偶机制解为节面I走向45°,倾角70°,滑动角-61°;节面II走向167°,倾角35°,滑动角-143°,矩震级为M_(W)3.91,最佳矩心深度为7 km。综合精定位后地震序列的时空分布特征、震源机制解信息、S-P走时差、区域地质构造和地震活动性探讨此次地震的发震构造及孕震环境,结果表明:此次震群不是前震序列,而是一次普通的3~4级震群活动。地震序列在不同阶段的时空演化过程可能是由至少2条存在一定夹角的断层结构在高应力和区域的温泉地热活动引发。
Based on the broadband seismic waveform data and seismic phase reports produced by the Yunnan Seismic Network and the Tengchong Volcano Network,as well as the latest developed high-resolution common velocity model(Version 2.0)of the Crust in Sichuan-Yunnan region,the double-difference relative positioning method combined with waveform cross-correlation techniques is used to relocate 442 earthquakes in the Mangshi,Yunnan M_(L)4.0 earthquake sequence in 2023.The CAP method is used to invert the focal mechanism solution of the M_(L)≥3.5 earthquakes in the sequence,and the seismogenic mechanism of the sequence is studied in depth to explore whether this sequence is a foreshock sequence or just an ordinary earthquake swarm.Through the double-difference location method,precise locations of 363 earthquakes are obtained.Their epicenters are distributed in NE direction,and these earthquakes are distributed in a triangular shape.The optimal double-couple mechanism solution of the main shock,the M_(L)4.0 earthquake,is obtained through CAP waveform inversion:the nodal Plane I strikes 45°,the dip angle is 70°,and the sliding angle is-61°.The nodal Plane II has a strike of 167°,an inclination of 35°,a slip angle of-143°,a moment magnitude(M_(W))of 3.91,and an optimal depth of 7 km.The temporal and spatial distribution characteristics of this earthquake sequence,the focal mechanism solution information,the travel time difference(S-P),the regional geological structure and the earthquake activity through the comprehensive precise positioning are used to explore the seismogenic structure and the seismogenic environment of this earthquake swarm.The results show that this earthquake swarm is not a foreshock sequence,but an ordinary earthquake swarm(magnitudes between 3 to 4).This earthquake sequence occurred on at least two faults.The faults are in high stress state and form an angle.The underground fluid affected this earthquake sequence's evolution at different stages.
作者
杨云存
姜金钟
刘克骧
王华柳
孙自刚
杨铭昌
YANG Yuncun;JIANG Jinzhong;LIU Kexiang;WANG Hualiu;SUN Zigang;YANG Mingchang(Yunnan Earthquake Agency,Kunming 650224,Yunnan,China;Kunming Institute of Prediction,China Earthquake Administration,Kunming 650224,Yunnan,China)
出处
《地震研究》
北大核心
2025年第1期10-21,共12页
Journal of Seismological Research
基金
云南省地震局传帮带项目(CQ2-2023-01)
国家防震减灾重点区域减轻地震灾害损失能力建设云南子项目.
关键词
芒市震群
双差定位
CAP反演
地震活动性
流体扩散
the Mangshi earthquake swarm
double difference positioning
CAP inversion
earthquake activity
fluid diffusion
