Geological characteristics of dip slope type landslides occurred on hard shale dominant formation in the Green Tuff region : an example of the Oshinkoshin landslide area in the Shiretoko Peninsula, East Hokkaido, Japan

A study of the Shiretoko Peninsula, Japan, reveals that large-scale landslides in the Green Tuff region are closely linked to geological layers dominated by hard shale and interbedded soft tuffaceous rocks. These dip-slope type landslides, classified as hydrothermally altered rock slides or debris flows, originate from the presence of smectite-rich soft tuff layers within thick hard shale formations. The research highlights that the Oshinkoshin landslide area exemplifies this relationship, with variations in scale—from massive rock slides to smaller debris flows—depending on the composition and structure of the moving material. This finding underscores the critical role of stratigraphic layering and mineralogical properties in landslide susceptibility within hard shale-dominated terrains.

MAEDA, H., KOHNO, M., HASEBE, S., SAWANO, H., & HIGAKI, S. (2014). Geological characteristics of dip slope type landslides occurred on hard shale dominant formation in the Green Tuff region : an example of the Oshinkoshin landslide area in the Shiretoko Peninsula, East Hokkaido, Japan. Journal of the Japan Landslide Society, 51(3), 81–89. https://doi.org/10.3313/jls.51.81