Rainfall-induced landslide risk at Lushan, Taiwan

Landslide is a frequently encountered problem in Taiwan during the heavy rainfall and typhoon seasons (July to September). Assessing the risk of landslide is a challenging task facing both the engineering communities and local authorities. In this paper we present a framework for analyzing the rainfall-induced landslide risk and demonstrate it with a case study of Lushan hot-spring district in Nantou County in central Taiwan. This framework consists of three parts: (1) an approach for determining the conditional probability of landslide under different scenarios, (2) a procedure for estimating the landslide-induced losses, and (3) a procedure for computing the total landslide risk. The results of the detailed case study of the total landslide risk in the Lushan hot-spring district show that the proposed methodology is an effective approach for landslide risk assessment. Use of the methodology for assessing the cost-benefit of an engineering mitigation work proposal is also presented.