Abstract
From 4th to 8th July 2018, heavy rainfall was recorded in the Reihoku district in Fukui Prefecture. In particular, rainfall of 30 mm/hour continued for 6 hours from midnight on 7th July, causing a rapid rise in total precipitation. In this report, we describe the result of investigating the shape of slope failures caused by this heavy rainfall from aerial photographs taken by Unmanned Aerial Vehicle. In addition, soil mechanics parameters were determined by laboratory tests on soil samples collected from the site and change in safety factors of the slopes before and after the rainfall was evaluated by a slope stability analysis.
