Development of shallow landslide hazard maps by combining continuous rainfall scenarios with physically based model

A methodology of shallow landslide hazard mapping by combining continuous rainfall scenarios with a physically based model was suggested and its validity and applicability was evaluated. The continuous rainfall scenarios were selected based on the critical amounts of continuous rainfall in study areas that were calculated from infiltration analyses. To this end, the data of terrain, soil depth, various geo-hydraulic and -mechanical input was collected for Mt. Guryong in Seoul, Mt. Myeogjo in Yongin, and the Gallam basin in Samcheok, while initial conditions were set up by applying each area's annually effective rainfall intensity. It was deduced that infiltration capacity of soil was higher as soil-water characteristic curve's gradient was gentle, and that it was the most decisive factor, together with slope agle, increasing landslide susceptibilities. landslide hazard maps were produced for each study area by transient infiltration analyses applying continuous rainfalls to the physically based model. landslide hazardous areas drastically increased and became predominant when continuous rainfall accumulated more than 250 mm. This also accorded with the recorded continuous rainfall amounts that have actually triggered landslides. As a result of evaluating the applicability of landslide hazard maps, its relevance as a conservative decision-supportive index was able to be deduced. By discussing limitations of the current results in this study, required improvement plans were suggested to ultimately realize the advanced management of landslide hazards based on continuos rainfall and physically based models.