A crucial component of hazard assessment and disaster mitigation planning for large-scale landslide events is the evaluation of the possible area that may be endangered by the moving mass. Volume estimation and insitu investigation of landslides are frequently used to identify possibly affected areas. Estimation of the actual landslide
scarps, subsequent flow pathways of the moving mass, and potentially at-risk areas is highly uncertain because the toe of the failure surface is often covered by the material released during the landslide. This uncertainty is particularly substantial if thorough postevent surveys or on-site drilling investigations have yet to be conducted. The estimation of landslide volume based on only pre- and post-event digital elevation models is highly uncertain when the detailed height of the actual landslide failure surface is unknown. Accordingly, the development of quick and easy-to-use tools that can determine the approximate distribution of the final deposit, the associated endangered area, and the landslide failure surface remains crucial.
Key Words: landslide-prone area of high uncertainty, idealized curved surface, landslide failure surface and endangered
area, assessment indicators