Risk of Rainfall-Triggered Landslide Disasters Under Climate Change by Applying Critical Line Method to NHRCM05

Abstract

We present a study on the future changes of landslide risk in Japan by applying the critical line method to the 5-km regional climate model of NHRCM05. From the six datasets of NHRCM05, we extracted effective rainfall events from the parameter of surface precipitation without any interpolation. In all extracted rainfall events, the critical line method was applied to obtain the frequency of landslide occurrence at each 1 by 1-km grid in the whole Japan. We exhibit the future changes of nationwide landslide risk distribution, monthly occurrence frequency in each geographical region, and occurrence trend in each prefecture. Additionally, from a different perspective, we reveal the relation between landslide risk trend and the geological feature of plate tectonics. As a result, the landslide risk is higher in the early summer of July in west Japan and in the late summer of September in east Japan. Particularly, the analysis shows a significant increasing trend of landslide risk in the Hokkaido area.