The Active Characteristics of Xianshuihe Fault in Holocene

Abstract

The Xianshuihe fault is an important strike - slip and strong seismogenic zone in West China. The active fault traces are controlled by existing Xianshuihe fault in bed rock and indicate the feature of arrangement in en echelon. Fault produced landforms such as offset streams, offset terraces, fault scarps, side - hell ridges and sag ponds are indicators of violent displacements on the fault and strong seismic activities since Holocene. Some pieces of information indicate that the long term slip rates of the Xianshuihe fault are remarkably different among the north and the south segments of the fault. It is 15 ± 5mm/y for the north of Qianning and 5.5mm/y for the Kangding fault south of Qianning. The discrepancy of slip rates along the Xianshuihe fault might be the basic reason which cause the difference in seismic activity of the fault. At last, the large earthquake trend on the Xianshuihe fault in the coming future has been discussed in this paper based on slip rates and co-seismic displacements and we believe that the segment of 40km long between Daofu and Qianning might be the most probably candidate one for an earthquake with magnitude about 7.