Abstract:

Xianshuihe Fault zone is a sinistral-slip fault system on the eastern margin of the Tibetan Plateau with high Quaternary activity and frequently historic earthquakes. And large landslides are distributed along the fault zone. This paper investigated the landslide distribution characteristics in an approximately 7,339 km² area and adopted Weight-of-Evidence Model (WOE) to develop landslide susceptibility evaluation. A detailed landslide inventory was prepared with a total of 415 landslides. Eleven landslide-causative factors were analyzed including slope angle, slope aspect, altitude, planform curvature, topographic wetness index (TWI), active fault, lithology, annual rainfall, rivers, roads and the NDVI of the study area. Susceptibility mapping schemes with WOE model were put out in this study and the assessment result with ROC method showed that the WOE model had got well result responses. The landslide susceptibility in the study area is controlled by the activity of Xianshuihe Fault zone, and is divided into five levels including no susceptible, low susceptible, moderate susceptible, high susceptible and very high susceptible according to landslide susceptible degree. The areas with very high and high landslide susceptibility are mainly distributed on both sides of Xianshuihe Fault zone from Donggu to Daofu County as well as Kangding County and Moxi town nearby. The moderate susceptibility areas are mostly along the tributaries of the deepcutting valleys and the roads. Besides, the low and no susceptibility areas are mostly distributed on high mountain areas where human engineering activity is weak, as well as areas where is relatively flat. The evaluation results reflect that the current situation of geological disasters in Xianshuihe Fault zone is well. The result can be used for the planning of geological disaster prevention and the major construction in the region.

Key words: Tibetan Plateau, Xianshuihe Fault, landslide, susceptibility evaluation, WOE model