Trends regarding range of rainfall indexes with snake line plots based on Radar‐raingauge analyzed precipitation for when major sediment movement phenomena occurred

Takuya NISHIUCHI, Kaho KUNITA, Shin‐ichiro HAYASHI, Yusuke SAKAI, Gaku KITAMOTO, Megumi KOSUGI and Satoshi YAMAMOTO

Abstract

Snake line plots for 52 major sediment movements, which have caused human and property damage in Japan, were created with rainfall indexes. The snake line plots were evaluated using rainfall indexes:1) 60 minutes accumulated rainfall vs soil water index;2) 60 minutes accumulated rainfall vs effective rainfall (half‐life 72 hours);3) probabilistic 60 minutes accumulated rainfall vs probabilistic soil water index. We quantitatively identified the range of critical rainfall indexes of each sediment movement (debris flow, slope failure, sediment‐laden flood, and deep catastrophic rapid landslide).

Key words

sediment movement, Radar‐raingauge analyzed precipitation, rainfall index, snake line plots, critical rainfall for occurrence of sediment movement