Analysing factors of slope failure and creation of slope failure risk map in mountainous river using GIS

Keita NAMBU, Satoru SHIBUYA, Takahisa NISHIOKA, Hiromasa YAMASHITA


In this paper, various factors such as landform and geological characteristics were analyzed with relevant digital data maps for the slope failures that were caused by heavy rainfall in the event of Typhoon No. 12 in 2011. By using 50m x 50m mesh GIS data, a total of 213 slope failures were analyzed by highlighting the hit rate with reference to various factors such as catchment area, slope angle, geology, landslide, terrain curvature and vegetation. A few characteristic features were manifested; e. g., area at the geological boundary between igneous rock and sedimentary rock shows a high risk of slope failure. Based on the results of the factor analysis, a slope failure risk map was created using GIS data effectively. Using this risk map, the extraction and use of danger areas of disasters including debris flow were verified.

Key words

GIS, slope failure, mountainous river, risk map, geological characteristics