2022 Volume 63 Issue 4 Pages 174-184
Previous studies have reported various topographical features involved in shallow landslides and those involved in catastrophic landslides. However, the difference between the topographical features involved in shallow landslides and those involved in catastrophic landslides under the consideration of the definition of topographical map used for the interpretation has not been organized sufficiently. In this study, we organized the topography of slopes in each of the areas where shallow landslides and catastrophic landslides occurred intensively. In case of the study of shallow landslides, we interpretated the topography of the landslide and non-landslide sites using 1：25,000 topographical maps to extract topographic features recognized in the landslide site using statistical analytics. In case of the study of catastrophic landslides, we reviewed a previous study that interpreted the micro-topography of slopes where catastrophic landslides occurred, using high-resolution DEMs （Digital Elevation Model） before the occurrence of the landslides. Results of the study of shallow landslide revealed that the following features were characteristically recognized on slopes where shallow landslides occurred： 1） convex slope, 2） valley slope and 3） angle of over 40 degrees. The previous study of catastrophic landslides revealed that the following features were commonly recognized in most of the slopes： i） the small scarps along their future crown, ii） irregularly undulating terrains below the small scarps and iii） horseshoe knick lines in the lower part of the slopes. These topographical features might be worthy of paying our attention for identifying unstable slopes susceptible to landslides by map interpretation. Additionally, 1：25,000 topographical maps and high-resolution DEMs should be useful for identifying unstable slopes susceptible to shallow landslides and catastrophic landslides, respectively.
