Current activity characteristics of Xianshuihe fault zone and its relationship with strong earthquakes based on fault-crossing measurements

This paper employed the fault-crossing deformation data about three decades (1982—2015) along the Xianshuihe fault zone to analyze fault activity characteristics and its relationship with adjacent strong earthquakes by using the three-dimensional movement model of fault and principal component analysis method. The preliminary results show that the Xianshuihe fault zone exhibits the left-lateral strike-slip features during the observation period (1982—2015), and the fault activity is different along each segments, the activity rates of Luhuo and Daofu segments are greater than that of Qianning segment, the Qianning segment tends to be locked. The series of fault activity parameters have obviously linear movement characteristic in the observation period, but in individual period, they show accelerating or turning deviating from the straight line. In addition, the principal component analyses of fault activity parameters show that the principal components and composite indicator of the fault horizontal strike-slip cumulant and horizontal tensional or compressive cumulant change original trend or break the trend respectively in the years 2001, 2006, 2010 and 2012, and the first principal component of fault vertical activity cumulant changes a little in 2013. These anomalies may be related with the 2001 western Kunlunshan Pass M_S8.1, 2008 Wenchuan M_S8.0, 2010 Yushu M_S7.1 and 2013 Lushan M_S7.0 earthquakes, belonging to the precursor, coseismic or postseismic effects of these strong earthquakes, respectively.