Investigation on the Wide-Area Slope Stability Using Open Data of Topography Before and After the Disaster

Abstract

Using open topographic data before and after the damage caused by the 2018 Hokkaido Eastern Iburi Earthquake, the stability of a wide area slope in Atsuma-cho was evaluated using GIS software. Straight slip method was used to evaluate the stability of the slopes, with a view to linking the results with practical design. Calculation parameters for straight slip were determined based on the results of previous surveys and numerical elevation models before and after the disaster. As a result, although the range of unstable slopes obtained from the analysis covered the actual slope failure area, a wider range of unstable areas were extracted. The horizontal seismic intensity, Kh, was set to a value higher than the maximum value of the back-calculated value to ensure a safe evaluation, and this is assumed to be a contributing factor.