Landslide susceptibility evaluated by 1-in-50yr values of Soil Water Index and hourly precipitation

2017 Fiscal Year Final Research Report

• Project/Area Number: 26282080
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Geography
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: MATSUYAMA Hiroshi 首都大学東京, 都市環境科学研究科, 教授 (50264586)
• Co-Investigator(Kenkyū-buntansha): 齋藤 仁 関東学院大学, 経済学部, 准教授 (00709628) ; 泉 岳樹 首都大学東京, 都市環境科学研究科, 助教 (10336513) ; 中山 大地 首都大学東京, 都市環境科学研究科, 助教 (90336511)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 土壌雨量指数 / 1 時間雨量 / 解析雨量 / 土砂災害 / CL (Critical Line） / 九州北部豪雨 / 無人航空機 / 空中三角測量

Outline of Final Research Achievements

We investigated rainfall conditions of the occurrence of landslides by using hourly precipitation (an index of short-term precipitation) and Soil Water Index (SWI, an index of long-term precipitation that is calculated by inputting hourly precipitation data to the three-stage tank model). At first, we respectively obtained the spatial distribution of 1-in-50yr hourly precipitation and 1-in-50yr SWI throughout Japan. Next, we investigated the relationship between hourly precipitation and SWI when landlides occurred in 2006-2008. Among all 816 cases, 806 landslides occurred when both hourly precipitation and SWI were smaller than respective 1-in-50yr values. Namely, the findings of this study might make us to re-consider the landslide susceptibility in Japan.

Free Research Field

水文気象学，地理情報科学