Spatio-Temporal Landslide Hazard Mapping Using Coupled Hydrological Model in Mt Umyeon, Seoul

Abstract

Landslide hazard maps are important for risk management and land-use planning in mountainous countries such as Korea. The aim of this study was to produce and evaluate a shallow landslide hazard map using a physically based slope stability model coupling with hydrological models in Mt Umyeon, South Korea. The incorporation of a rainfall frequency–duration relationship of heavy rainfall into the assessment of landslide hazard provides a practical way to include climate information into the estimation of shallow landslide hazard. A GIS-based landslide inventory map of 146 landslide locations was prepared using data from previous reports, aerial photographic interpretation, and extensive field work. And 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. A combined approach of Quasi-dynamic wetness (QDWI) and infinite slope model was used to prepare landslide hazard maps of different durations i.e. considering 17hr duration with average rainfall intensity (case I), 15hr duration with average rainfall intensity (case II) and the last 2hr duration and average intensity added in case II (case III). The results of the analysis were verified using the landslide location data. Receiver operating curve was used to compare all cases. The case III shows satisfactory agreement between hazard map and the existing data on landslide locations with 82.2% accuracy of the model. The results of this study can therefore be used to mitigate landslide-induced hazards and to plan land-use.