东昆仑断裂玛沁-玛曲段断层结构和应力场特征研究

为研究东昆仑断裂玛沁-玛曲段的活动特征，利用双差定位法对东昆仑断裂玛沁-玛曲段2009-01～2018-09中小地震进行重新定位，并基于CAP(cut and paste)方法反演研究区域3.5级以上地震的震源机制解。结果显示，地震活动沿断裂带分段特征明显，在101°E附近地震沿阿万仓断裂分布，近10 a来玛沁至若尔盖的地震空区现象还在持续；东昆仑断裂玛沁-玛曲段震源深度主要分布在2～30 km范围内；研究区域主压应力为NEE向，主张应力为NNW向。研究结果为东昆仑断裂玛沁-玛曲段因受阿万仓断裂的吸收转换导致在玛沁-玛曲段滑动速率减弱的结论提供了地震学方面的证据。

Study on Fault Structure and Stress Field Characteristics of Maqin-Maqu Section of East Kunlun Fault

To study the activity characteristics of the Maqin-Maqu section of the east Kunlun fault, through the double-difference location algorithm, we relocate the small and medium seismic events in the Maqin-Maqu section of the east Kunlun fault from January 2009 to September 2018. Based on the CAP(cut and paste) method, we invert the focal mechanism solutions of earthquakes over magnitude 3.5 in the study area. The results show that the segmentation characteristics of seismic activity along the fault zone are obvious: the earthquake distribution around 101° E unfolds along the Awancang fault and the earthquake airspace phenomenon from Maqin to Zoige in the past 10 years has continued. The focal depth of the Maqin-Maqu segment of the east Kunlun fault is mainly distributed in the range of 2 to 30 km. The main compressive stress in the studied area is NEE, while the tensile stress is towards NNW. The results of the study provide seismological evidence for the conclusion that the slip rate of the Maqin-Maqu section weakened due to the absorption conversion of the Awancang fault in the east Kunlun fault.