浙江珊溪水库震群活动的构造力学环境研究

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中图分类号：P315 文献标志码：A 文章编号：1000-0844（2026）01—0217—12

Tectonic stress environment of the earthquake swarm activity in Shanxi Reservoir， Zhejiang Province

WANG Ganjiao 1，2 ，SHENG Shuzhong³，XIAO Jian¹，LI Xiaoxue4，LI Minjuan 4. ， GUO Yufan1 ，LI Qingwu1，DONG Jun¹ ， ZHA Xiaohui1， ZENG Wenjingl （1.Jiangxi Earthquake Agency，Nanchang 330096， Jiangxi， China; 2.ObseruatoryforGeodynamicoftheEast YangtzeBlock inJujiang，Jiangxi Province，Jiujiang 3320o6，Jiangxi，China; 3.East China University of Technology，Nanchang 3300l3， Jiangxi， China; 4.Gansu Earthquake Agency，Lanzhou 3oooo，Gansu，China）

Abstract： The earthquake swarm activity in the Shanxi Reservoir， Zhejiang Province， in September 20l4 has attracted widespread attention. However， the understanding of its tectonic stress environment remains controversial. Therefore，using earthquake catalogs and phase observation reports for Shanxi Reservoir from September 20l4 to April 2Ol5， this study calculated the b -value of the earthquake swarm，performed precise relocation using the double-difference relocation method，and analyzed the seismogenic structure and genetic mechanism of the swarm activity by combining focal mechanism solutions and stress field inversion results. This research indicates the following：（1） The spatial distribution of relocated hypocenters and the statistical analysis of nodal planes from focal mechanism solutions both revealed distinct NW—SE-trending high-angle tectonic features，consistent with the structural characteristics of the third branch fault of the Shuangxi—Jiaoxiyang fault. （2） The b -value of the earthquake swarm was O.6，reflecting reservoir-induced seismic characteristics with small magnitude and high frequency. Most focal mechanism solutions of ML≥3.0 earthquakes in the swarm were of the strike-slip type，consistent with the tectonic features of the principal stress axes of the regional stress field obtained from small earthquake polarity inversion. Accordingly， this study concludes that the swarm represents a tectonic-reservoir-induced earthquake，resulting from mechanical instability of the third branch fault of the Shuangxi-Jiaoxiyang fault under the control of the regional stress field.

Keywords： Shanxi Reservoir; b -value;precise relocation；focal mechanism；tectonic stress field

0 引言

珊溪水库位于经济发达、人口密集的温州市，为温州地区提供了坚实的防洪保障和优质的电力资源。（剩余17972字）