Abstract
Based on aerial photographs interpretation and DEM's analysis within the Imo River basin and its surrounding area, the present paper revealed several possible causative factors that are possibly responsible for the landslides induced by the Mid-Niigata Prefecture earthquake in 2004. The study results show that, 73% of the earthquake-induced landslide occurred within pre-existing landslide sites in the study area. As geomorphological factors, earthquake-induced landslides related to the convexity and lower part inclination of pre-earthquake ground surface, and the landslide occurrence ratio tends to increase with the values of these factors. As geological factors, relatively larger landslides tend to occur on slopes composed of sandstone, sandy siltstone, and alternation of sandstone and mudstone, and the landslide occurrence ratio is relatively higher compared to mudstone.
