鲜水河断裂带断层蠕变观测与地震

利用断层蠕变观测数据,采用断层运动学分析方法、主成分分析法,综合研究鲜水河断裂带现今运动学特征,并探讨其与断裂带附近中强震孕育-发生及周边大尺度强震的可能关系。结果表明:1)鲜水河断裂带现今构造运动以左旋走滑为主,但错动方式并不唯一,在个别时段也出现短暂的右旋走滑。此外,鲜水河断裂带还表现出明显的分段活动特征。2)鲜水河断裂带断层蠕变观测在白玉M_S5.5地震、雅江M_S6.0地震、汶川M_S8.0地震、芦山M_S7.0地震以及康定M_S6.3地震前均出现了不同程度的形变异常,属于这几次地震的前兆反应,而鲜水河断裂带于2001年底开始的大幅度拉张运动,主要是受2001-11-14昆仑山口西M_S8.1地震震后大区域应力场调整影响所致。

Creep-Meter Observation and Earthquakes along the Xianshuihe Fault Zone

Based on creep meter data from Xianshuihe fault zone, we analyze, by fault kinematics and principal component analysis method, fault activity characteristics and their relationship with the preparation-occurrence of moderate earthquakes around the Xianshuihe fault and great earthquakes in a large-scale area nearby. The results show that: 1) Current kinematic characteristics of Xianshuihe fault are mainly left strike-slip, the dislocation mode is not singlular but turns dextral strike-slip multiple times; 2) Xianshuihe fault zone creep observation shows anomaly variations before the Baiyu MS5.5, Wenchuan MS8.0, Lushan MS7.0 earthquakes, along with the Kangding MS6.3 earthquake, which is a precursor to those earthquakes; further, the amplitude extension beginning at the end of 2001 is affected by the large regional stress field adjustment after the west Kunlun mountain pass MS8.1 earthquake in 14 November, 2001.