INDICATORS FOR ASSESSING RISK OF LANDSLIDE OCCURRENCE USING THE SEDIMENT DISASTER RAINFALL INDEX BASED ON ANALYTICAL RAINFALL

Abstract

 To evaluate risk of landslide occurrence based on rainfall, which is a trigger factor, the 1st tank of Soil Rainfall Index tank model as well as the 60-minute cumulative rainfall used by the Landslide Information Delivery System as risk assessment indexes using XRAIN real time precipitation data, were recalculated for 15 years from 2006 to 2021 using the analytical rainfall, and the results were examined. Due to the large variation in the values, the probability of event occurrence per unit of time was calculated using a Poisson distribution. The results show that the probabilities are substantial for almost all of Kyushu, the Pacific coast of Shikoku and the Kii Peninsula, confirming that the probability of landslides occurring in these areas is large due to regular heavy rainfall.