Abstract: Hazard assessment is a key issue in risk assessment and risk control of regional landslide disaster. With Yunyang County, Chongqing City in the Three Gorges Reservoir area as study area, the stepwise discriminant method was employed to screen key indices (slope, elevation, profile curvature, terrain humidity index, rock and soil types, vegetation coverage and distance to roads) from the initial index system. The spatial probability of landslide was obtained by susceptibility zoning of the whole study area using logistic regression model. Furthermore,the study area was divided into non-reservoir-bank area (beyond 5 km to the water system) and reservoir bank area (within 5 km to the water system). For the time probability of landslide in non-reservoir-bank area, different return periods of rainfall was considered, while for the reservoir bank area, the combination of different reservoir water levels and different rainfall return periods was considered. According to the final comprehensive time probability and susceptibility results, the zoning map of regional landslide hazard risk in Yunyang County was obtained. Results suggest that landslides in the area mainly occur under the combined actions of heavy rainfall and low reservoir water level. Accounting for 52.7% of the total area of Yunyang County, areas of high risks distributed in construction land areas around cities and towns with intense human engineering activities along the main stream of the Yangtze River and its tributaries. The research findings offer reference for improving the accuracy of risk assessment and developing the theory of landslide hazard risk assessment.

Key words: landslide hazards, hazard assessment, reservoir water level, rainfall, Yunyang County