GIS Application in Landslide Hazard Analysis – An Example from the Shihmen Reservoir Catchment Area in Northern Taiwan

Abstract: This study used GIS as a tool to map storm-induced landslides from SPOT5 images. Digital elevation model (DEM) of 10m x 10m resolution was used to extract geomorphic landslide causative factors: slope gradient, slope roughness, tangential curvature, relative slope height, total slope height and wetness index etc. Digital geological map was used to extract geologic causative factors: lithology and distance to fault trace. SPOT image taken prior to a typhoon was also used to calculate an environmental factor- NDVI (normalized differential vegetation index). Triggering factor was tested to be the maximum rainfall intensity. These causative factors and triggering factors were used to build a landslide susceptibility model via logistic regression. Validation result shows that this model could be used for the prediction of future landslides. GIS is a useful tool for the construction of landslide prediction model and for application in regional planning, hazard mitigation, and sediments yield estimation