安宁河-则木河-小江断裂带闭锁特征研究

分别利用1999~2007年和2009~2014年多期GPS观测获取的水平速度场数据，采用负位错反演模型，研究安宁河-则木河-小江断裂带的滑动速率和闭锁程度空间分布特征，同时结合历史强震记录，分析这几条断裂的地震危险性。结果显示：1)安宁河断裂和则木河断裂滑动速率受汶川地震影响有所减弱，小江断裂滑动速率在汶川地震后基本保持不变；2)则木河断裂中段和小江断裂的断层闭锁程度受汶川地震影响而显著加强，安宁河断裂、则木河断裂的西昌和巧家以北区域的闭锁程度基本不受汶川地震的影响；3)汶川地震发生前后，安宁河断裂的石棉-冕宁段、则木河断裂的西昌与巧家以北区域和小江断裂的通海-建水段闭锁深度均在20 km以上。结合历史强震记录和其他方法的研究结果，三者在未来一段时间内发生强震的危险性要高于其他断层段。

Study on the Locking Characteristics of Anninghe-Zemuhe-Xiaojiang Fault Zone

In this paper, we inversed for the slip rate and spatial fault locking of the Anninghe-Zemuhe-Xiaojiang fault zone based on a negative dislocation with horizontal GPS velocity data from 1999 to 2007 and 2009 to 2014. Using the inversion result and the historical earthquakes, we analyze the potential for a large earthquake. The result shows the Wenchuan earthquake enhanced the locking of Xiaojiang and the middle segment of Zemuhe, but didn’t affect the locking of Anninghe or the southern and northern segment of Zemuhe. Moreover, the northern section of Anninghe, the southern and northern segment of Zemuhe , the southern segment of Xiaojiang are strongly locked before and after the Wenchuan earthquake, with a locking depth of more than 20 km. Considering historical earthquakes and other results, we conclude that these segments are seismogenic faults with large earthquake potential.