LANDSLIDE SUSCEPTIBILITY ASSESSMENT IN ACTIVE SEISMIC ZONE -WITH A CASE STUDY OF WENCHUAN

The Ms 8.0 Wenchuan earthquake, occurred on 12 May 2008 in Sichuan Province, caused enormous property damages and human casualties. In order to remove threat from the secondary landslides effectively, this study used techniques of remote sensing and GIS to generate susceptibility map, taking the case of Wenchuan County. The factors controlling landslides are obtained from geological maps and DEM, including relief amplitude, lithology, seismic intensity, distance to faults and rivers. Furthermore, this paper presents quantitative analysis of relationship between number and area of the landslides and factors in the study area. Based on this analysis, the probability predicting the possibility of landslide occurrence has been calculated applying information value method and logistic regression separately. The study zone was ultimately categorized into five classes, specifically, "extremely low", "low", "moderate", "high" and "very high". These results have been proved to reflect closely the spatial distributions of landslides in the study area.