北京大学学报（自然科学版）2025，Vol.61Issue(4)：659-667,9.DOI:10.13209/j.0479-8023.2024.093
则木河-小江断裂带小震震源机制解与构造应力场研究
Focal Mechanisms of Small Earthquakes and Tectonic Stress Field Study in Zemuhe-Xiaojiang Fault
摘要
Abstract
This study employs a broadband seismometers network around the Zemuhe-Anninghe Fault zone in Yunnan to detect and locate earthquakes from 2015 to 2019,yielding 11091 event locations.Seismic activity is concentrated at the intersection of the Zemuhe Fault and the Xiaojiang Fault,with the locations revealing the spatial relationship between these two fault zones.The distribution of earthquakes shows significant spatial clustering and indicates numerous secondary structures beyond the main faults.Based on these high-precision microearthquake locations,1462 focal mechanism solutions were calculated,predominantly showing strike-slip movements.At the intersection of the Zemuhe and Xiaojiang faults,a concentration of normal fault type earthquakes aligns with the characteristics of the regional extensional basin.Average focal mechanism solutions and structural stress field inversion results indicate some rotation of stress fields across different regions;from north to south,the principal stress axis rotates clockwise by approximately 15°.The southern segment of the Zemuhe Fault and the northern segment of the Xiaojiang Fault have R values of 0.28 and 0.10,respectively,reflecting characteristics of both strike-slip and extension.The complexity of the stress fields within the study area reflects the presence of multiple scales of tectonic stress loading patterns.关键词
微震检测/震源机制解/构造应力场/则木河-小江断裂带Key words
microseismic detection/focal mechanism/tectonic stress field/Zemuhe-Xiaojiang Fault引用本文复制引用
汪龙潭,朴健,周仕勇..则木河-小江断裂带小震震源机制解与构造应力场研究[J].北京大学学报（自然科学版）,2025,61(4):659-667,9.基金项目
国家重点研发计划(2023YFC3012002)和国家自然科学基金(42474069)资助 （2023YFC3012002）
