Sediment disasters caused by Typhoon Hagibis on October, 2019 in Tohoku region

Michiya IRASAWA, Shinjiro MATSUO, Mizuho ARAI, Masahiro KAIBORI, Ching-Ying TSOU, Takashi YAMADA, Mio KASAI, Takashi KOI, Nobuaki KATO, Taeko WAKAHARA, Daisuke HIGAKI, Hajime IKEDA, Yoshiharu ISHIKAWA, Kenichi ARAI, Shinji HIROSE, Tatsuya SATO, Hideki KAWATABATA, Manabu KOUBU, Satoshi NIWA, Kazuhiro SUGAWARA, Hiroyuki MATSUSAKA, Nobuyuki TADA and Toshiyuki KON

Abstract

Large and powerful Typhoon Hagibis (1919) made landfall on the Izu Peninsula on 12 th October 2019, and it brought widespread and record-breaking torrential rain across Japan, especially in Eastern Japan. Emergency warning was issued in Tokyo and 12 prefectures, and many slope failures and debris flows were caused. It marked the largest number of sediment disaster occurrences by a typhoon since 1982 that the statistics have been started to be recorded. 952 sediment disasters were caused by the typhoon (as of 24 th December 2019), and 16 people were killed and one person is missing. In Tohoku region, most disasters happened in Iwate, Miyagi, and Fukushima prefectures. From 1 : 00 am, 12 th October to 12 : 00 am, 13 th October (two days) total precipitation (observed by AMeDAS of Japan Meteorological Agency) was 594 mm in Hippo, Marumori-machi, Miyagi prefecture, and 466.5 mm in Fudai, Iwate prefecture. From the above, Japan Society of Erosion Control Engineering organized“Emergency investigation team for the sediment disasters in Tohoku region caused by Typhoon Hagibis 2019”and performed the investigation three times.

Key words

debris runoff, debris disaster, slope failure, surface runoff, woody debris