Combination of Rainfall Thresholds and Susceptibility Maps for Early Warning Purposes for Shallow Landslides at Regional Scale in Taiwan

In this study, the development of landslide susceptibility and determination of rainfall threshold for shallow landslides is the main purpose for the prevention of slope disaster. For appliance of the practical operation of disaster prevention, almost 185,000 slope units are used to calculate landslide susceptibility and determine the rainfall threshold of shallow landslides, which are a reference of preparation for slope disasters. Time of occurrence of 941 landslides are collected through field investigation, and rainfall pattern of each landslides are analyzed to clarify the relation between landslide and rainfall. Logistic regression (LR) analysis was performed to evaluate landslide susceptibility and establish the assessment method of the rainfall threshold of landslide by using I3–R24 rainfall thresholds. After verification of rainfall-induced landslide in Typhoon Meranti (2016), the result show that the early warning model is suitable for alerting serious swarm of landslides.