华南地震2023，Vol.43Issue(4)：126-135,10.DOI:10.13512/j.hndz.2023.04.16
2023年广东河源4.3级和东源4.5级地震余震分布及震源机制解特征
The Aftershock Distribution and Focal Mechanism Solutions Characteristics of the Heyuan MS4.3 and Dongyuan MS4.5 Earthquakes in Guangdong in 2023
摘要
Abstract
On February 11th,2023,an MS4.3 earthquake occurred in Yuancheng District,Heyuan City,Guangdong Province.Just 25 days later,an MS4.5 earthquake occurred in Dongyuan County.The two earthquakes were both located in the Xinfengjiang reservoir area.In order to study the source characteristics of the main shock,the spatial distribution of aftershock sequences,and the characteristics and mechanism of reservoir-induced earthquakes,this paper analyzes the distribution characteristics of the aftershocks of the two earthquakes,and uses the gCAP and FOCMEC methods to invert the focal mechanism solution of main shocks.The results show that Heyuan MS4.3 earthquake is a positive strike-slip earthquake event,and the distribution of aftershocks is elliptical.The orientation of the P-axis is NW direction,and the pitch angle is relatively vertical,which is consistent with the stress field characteristics of the canyon and dam area.It is judged that Heyuan earthquake may be controlled by multiple fractures and affected by water gravity,which is a normal stress release process.The Dongyuan MS4.5 earthquake occurred in the western area of the reservoir basin,which is a left-lateral strike-slip earthquake.Combined with the linear distribution of the aftershock sequence in NNW-SSE direction,it is judged that the strike of the seismogenic fault is SSE direction,and the dip angle is nearly vertical.The orientation of the P-axis is NWW direction,and the pitch angle is nearly horizontal,which is consistent with the characteristics of the stress field on the west side of the Xichang area.The west side of reservior basin is a new seismic area with significant seismic activity since 2019,and has many similarities with the adjacent Xichang area.It is judged that there may be the same concealed"North 45º westward trending along the river fault"in the two regions.As the seepage activity of reservoir water extends from north to south,it induces a series of strong seismic activities in the Xichang area and the west side of the reservoir basin.Both areas are in the early seismogenic stage.Combining the characteristics of the old earthquake areas in the canyon and dam areas,it is necessary to focus on the characteristics of the stress field changes and strong earthquakes in the two new earthquake areas in the future.关键词
河源4.3级地震/东源4.5级地震/余震分布/震源机制解/FOCMEC方法/gCAP方法Key words
Heyuan MS4.3 earthquake/Dongyuan MS4.5 earthquake/Aftershock distribution/Focal mechanism solutions/FOCMEC method/gCAP method分类
天文与地球科学引用本文复制引用
姜喜姣,林庆西,陈修吾,朱腾,梁明..2023年广东河源4.3级和东源4.5级地震余震分布及震源机制解特征[J].华南地震,2023,43(4):126-135,10.基金项目
地震监测、预测、科研三结合课题(3JH-202301026) （3JH-202301026）
震情跟踪定向工作任务(2023010108) （2023010108）
广东省地震局青年地震科研基金(重点实验室开放基金)(GDDZZ202306)共同资助. （重点实验室开放基金）
