摘要
利用CAP方法反演2021年漾濞6.4级地震震源机制,并基于云南地区2015~2022年M≥3.0地震震源机制解结果,采用叠加应力场反演方法反演漾濞6.4级地震前后不同时段的应力张量方差空间分布特征;采用云南地区2013~2022年M≥3.0地震震源机制解结果分析震源区附近震源机制一致性参数的时序变化特征。结果表明:漾濞6.4级地震性质为右旋走滑型,矩震级M_(W)6.03,矩心深度5.8 km,节面Ⅰ走向39°、倾角75°,滑动角-16°;节面Ⅱ走向133°、倾角75°、滑动角-164°。应力张量方差空间演化特征显示,漾濞6.4级地震震源区附近应力张量方差经历了一个低值-显著升高-震前下降形成新低值-震后显著升高的变化过程。应力张量方差时间演化特征显示,漾濞6.4级地震震源区附近应力张量方差在地震前1~2 a达到最高值,后持续下降,下降至最低值后发生转折并趋势回升,整体呈正“V”字型,地震发生在正“V”字型转折后趋势回升阶段。应力张量方差的时空演化特征具有一致性。
We invert the focal mechanism of the 2021 Yangbi 6.4 earthquake by the CAP method.Based on the focal mechanism of M≥3.0 earthquakes in Yunnan province from 2015 to 2022,the spatial distribution of the stress tensor variance before and after the earthquake is inverted by the superimposed stress field inversion method.We then use the focal mechanism of M≥3.0 earthquakes in Yunnan from 2013—2022 to further analyze the temporal evolution characteristics of focal mechanism parameters.The results show that the Yangbi 6.4 earthquake is a right-lateral strike-slip earthquake,moment magnitude is M_(W)6.03,moment depth is 5.8 km,for nodal surface I,strike is 39°,dip angle is 75°,slip angle is-16°;for nodal plane II,strike is 133°,dip angle is 75°,slip angle is-164°.The spatial evolution of the stress tensor variance shows that the stress tensor variance near the earthquake area undergoes a process of “low value-significant increase-drop before the earthquake to form a new low value-significant increase after the earthquake.” The temporal evolution of the stress tensor variance shows that the stress tensor variance near the Yangbi 6.4 earthquake area reaches its highest value one to two years before the earthquake,then continues to decline,and then turns and trends back up after the lowest value,with an overall positive “V” shape.Earthquakes occur during a positive “V” turn followed by an upturn in trend.The spatiotemporal evolution of stress tensor variance is consistent.
作者
李见
陈佳
叶泵
李孝宾
杨建文
金明培
番邵辉
LI Jian;CHEN Jia;YE Beng;LI Xiaobin;YANG Jianwen;JIN Mingpei;FAN Shaohui(Yunnan Earthquake Agency,146 Beichen Road,Kunming 650224,China;Field Scientific Observation and Research Station on Crustal Tectonic Activities in Northwest Yunnan,Binhɑi Road,Dali 671000,China)
出处
《大地测量与地球动力学》
CSCD
北大核心
2024年第2期166-172,共7页
Journal of Geodesy and Geodynamics
基金
云南省地震局科技人员传帮带培养项目(CQ3-2021005)
云南省地震局青年基金(2023K09)
云南省重点研发计划(202203AC100003)。
关键词
漾濞6.4级地震
震源机制一致性
应力张量方差
时空演化
Yangbi 6.4 earthquake
focal mechanism consistency
variance of stress tensor
spatiotemporal evolution
