A study of unevenly distributed slope failures caused by orographic precipitation in Murakami City in August 2022 using transfer learning

Abstract

The large rainfall ovserved in Murakami City, Niigata Prefecture, on August 3-4, 2022, caused simultaneous slope failures on many slopes and debris flows were observed in the valley. Detailed observation of satellite and aerial photographs revealed that the collapse sites were unevenly distributed at the ridge boundaries. In order to find the causes, we analyzed the latent failure characteristics of the slope failures using transfer learning and the triggering factors based on the actual observed wind direction and the analyzed rainfall for each rainfall mesh from the beginning of the rainfall. The results suggest that the observed slope failures were caused by localized rainfall on the wind-back slope due to the orographic precipitation.