Shallow Landslide Susceptibility Modeling Incorporating Rainfall Statistics: A Case Study from the Deokjeok-ri Watershed, South Korea

Abstract

A physically based slope stability model was applied to predict topographic and climatic control on shallow landslide initiation processes in mountainous terrain. We applied two simple hydrological models, coupled with the infinite slope stability analysis, to the July 2006 landslide event in Deokjeok-ri, South Korea. The rainfall predicted to cause instability in each topographic element is characterized by duration and frequency of occurrence. The incorporation of a rainfall frequency-duration relationship into assessment of landslide susceptibility provides a practical way to include climate information into estimation of the relative potential for shallow landsliding. A GIS-based landslide inventory map of 748 landslide locations was prepared using data from previous reports, aerial photographic interpretation, and extensive field work. This landslide inventory was used to document sites of instability and to provide a test of model performance by comparing observed landslide locations with model predictions. The area under curve of QD-SLaM was 0.79, which means that the overall accuracy of the landslide susceptibility is 79% and the prediction result is good.