汶川地震前后红河断裂闭锁程度和滑动亏损研究

Research on Fault Locking and Fault Slip Deficit of the Honghe Fault before and after Wenchuan Earthquake

以1998～2007年和2009～2017年中国大陆水平GPS速度场为约束,基于块体-位错模型,研究2008年汶川地震前后红河断裂运动特征。结果表明,汶川地震后红河断裂平均右旋走滑速率约为4.5 mm/a,其北段走滑速率增大明显,中段次之,而南段明显减弱;倾滑速率北段减弱明显,中段和南段有所减弱。汶川地震后红河断裂闭锁程度和滑动亏损中、北段都有所增加,南段减弱较大;近期红河断裂滑动亏损北段达到10 mm/a以上,中段也在5～8 mm/a,平均闭锁深度在20 km左右。分析认为,汶川地震对红河断裂中、北段影响较小,南段影响较大。

This paper uses the horizontal GPS velocity field of the Chinese continent in 1998~2007 and 2009~2017 years as constraints.Based on the block-dislocation model,we study the movement characteristics of the Honghe fault before and after the 2008 Wenchuan earthquake.The results show that after the Wenchuan earthquake,the average right-lateral strike-slip rate of the Honghe fault is about 4.5 mm/a,and the strike-slip rate of the northern segment increases obviously,the strike-slip rate of the middle segment increases slightly,the strike-slip rate of the southern segment decreases obviously.The dip-slip rate on the northern segment of the Honghe fault decreases obviously,the middle and southern segments decrease slightly.After the Wenchuan earthquake,the locking and slip deficit on the northern segment of the Honghe fault increases slightly and the middle segment is the same,while the locking and slip deficit on the southern segment decreases significantly.Recently,the slip deficit on the northern segment of the Honghe fault is about 10 mm/a,the slip deficit on the middle segment is also 5~8 mm/a,and the average locking depth is about 20 km.The analysis suggests the impact of Wenchuan earthquake on the northern segment and the middle segment of the Honghe fault is relatively small,which has a great influence on its southern segment.