Coupled model for simulation of landslides and debris flows at local scale

This research connects different but sequential processes of slope failure: landslide occurrence, debris-flow initiation from landslides, and debris-flow propagation to lowlands. The coupled model presented in this study consists of a deterministic landslide susceptibility model that estimates the landslide source and local geomorphological mobilization criteria for selecting debris-flow initiation points, and an empirical debris-flow model that simulates the transport and propagation of failed materials from the identified source areas. The debris flow initiation in the spreading analysis was estimated from the landslide source by landslide analysis. Then, its inspection using the mobilization criteria was used to determine if the landslide transformed into a debris flow. While the geomorphological criteria were calibrated using data obtained from Gyeong-gi Province, the validation of the coupled approach was done at Mt. Woomyeon. In comparison with a landslide inventory map, the model simulations resulted in reasonable estimates of all the mountain hazards caused by slope failures as a sequential process on a local scale. The coupled analysis proposed in this study affirms that it is important to manage them together because of the correlation between landslides and debris flows. Thus, if it is parameterized and calibrated for local conditions the suggested model, linking landslides and debris flows with the mobilization analysis, provides a powerful tool for decision makers in territorial planning and disaster preparedness.