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. 

利用云南则木河–安宁河断裂带附近密集台阵的区域地震观测资料, 对台站覆盖区域2015—2019年的地震事件进行检测和定位, 得到11091个小震定位结果。微震活动集中在则木河断裂带与小江断裂带相交处, 定位结果较好地揭示了两条断裂带的空间关系。地震分布具有明显的空间丛集特征, 并显示大量主断层之外的次级结构。基于获得的高精度小震定位结果, 计算得到1462个震源机制解, 表明以走滑类型为主。在则木河断裂带与小江断裂带相交处, 集中分布许多正断层类型地震, 与该区域拉张盆地的特征吻合。平均震源机制解和构造应力场反演结果显示, 不同区域的应力场发生一定程度的旋转, 研究区自北向南主压应力轴顺时针旋转约15°, 则木河断裂带南段和小江断裂带北段R值分别为0.28和0.10, 具有走滑兼拉张的特征。研究区内应力场存在复杂性, 反映该区域具有多种尺度的构造应力加载模式。