LANDSLIDE SUSCEPTIBILITY ASSESSMENT IN JIUZHAIGOU SCENIC AREA WITH GIS BASED ON CERTAINTY FACTOR AND LOGISTIC REGRESSION MODEL

Thousands of coseismic landslides were induced by the Jiuzhaigou M_S7.0 earthquake on August 8th 2017, Sichuan, China. Thus, a tremendous volume of loose debris are extremely prone to convert into landslides and debris flow under rainfall. Therefore, it is necessary to conduct landslide susceptibility assessment in Jiuzhaigou Scenic area. Based on a large set of pre-and post-earthquake high-resolution satellite images and field investigation, a polygon-based interpretation of the coseismic landslides is carried out. In total, 1047 landslides are identified, covering an area of 3.88 km². The relationship between the spatial distribution of landslides and its influencing factors is analyzed. Nine factors including tectonic, topographic, geological and other factors are selected to evaluate the landslide susceptibility by certainty factor model and logistic regression model, as well as coupled model. The result shows that slope, aspect, elevation and lithology are the main factors controlling the spatial distribution of landslides. The susceptibility of landslide is divided into low(60.72%), moderate(24.18%), high(9.89%) and extremely high areas(5.21%). The high and extremely high areas covering an area of 99 km² including Tiger Lake and Panda Lake are distributed along the valleys. The assessment result of the coupled model is more reasonable than that of the single model and can be used as scientific reference for prevention of landslide hazard and segmented opening time of scenic area.