Slope Failures and Debris Flow Caused by 2018 July Heavy Rain along Katsuradani, Hida City, Gifu Prefecture, Japan

Abstract

Investigation results of the slope failures and debris flow which damaged the JR Takayama Line are reported. Two shallow landslides of 1,000 m³ order in volume occurred by the rainstorm in July, 2018. Failures were on the boundary between strongly weathered Jurassic Hida Granite and overlying soil. Failure materials moved rapidly and grew into debris flow involving valley bottom and valley side deposits especially in the lower part of the transportational area. At the upstream side of the embankment for railway resulting in overflowed and broken, debris of 9,000 m³ were deposited.