QUANTITATIVE HAZARD ASSESSMENT FOR LANDSLIDES AT DIFFERENT RECURRENCE AND VOLUME SCENARIOS

Quantitative assessment of regional hazard is an important item of risk analysis. In this paper, it aims to realize the spatial-temporal probability when induced factors are unavailable. For the Yuyangguan county, in the southwest Hubei province, China, we achieved landslide hazard probability at large scale combining the spatial probability, temporal and exceedance probability. We obtained the spatial probability of landslide-occurrence by Weights of Evidence model based on 9 indicators, including slope, elevation, aspect, plan curvature, lithology, et al.,with success rate 0.84 and prediction rate 0.74. Based on the assumption of a Poisson distribution, we obtained temporal probability for four return periods(5, 10, 20 and 50 years).Using the statistics of landslide magnitude and frequency, the exceedance probability was achieved for two volume scenarios(50000 cubic meters, 100, 000 cubic meters).Lastly, we obtained landslide hazard maps for four periods, from 5 to 50 years, and for landslide two volume scenarios(AL 50000m3, and AL 100000m3). The results showed that in ten years return period, landslide probability would be 0.2-0.3 and 0.1-0.2 respectively at two volume scenarios, mainly concentrate at the urban construction areas along both sides of Yuyangguan river. With the increase of recurrence period, the probability of landslide hazard would increase to 0.5-0.6, 0.3-0.4,with the affected area extended to Dongwan, Hutounao and Sanfangping. The conclusion can provide scientific support for urban construction in mountainous towns.