Simulation of landslides and debris flows at regional scale using coupled model

Abstract

This research attempts to connect different but sequential processes of slope failure: landslide occurrence, debris flow initiation from landslide and debris flow propagation to lowland. The suggested coupled model in this study comprises of a deterministic landslide susceptibility model to estimate landslide source, local geomorphological mobilization criteria to select debris flow initiation points and an empirical debris flow model to simulate the transport and propagation of failed materials from the identified source areas. The debris flow initiation in the spreading analysis was estimated from landslide source by landslide analysis and its inspection whether the landslide transforms to debris flow or not using the mobilization criteria. For the landslide assessment, a physically-based model was adopted for that it shows more consistent and concrete results than a statistical model, if the model is well simulated with ample data. On the other hand, a probabilistic model was used for the debris flow assessment since the process based models of debris flow are difficult to apply due to the complexity of the phenomenon and the variability of controlling factors. Between the landslide and debris flow analyses, mobilization criteria from landslide to debris flow were taken into account in the identification of debris flow initiation sources. A major task for the case study in Gyeong-gi province was to calibrate the topographic criteria from landslide to debris flow. In order to validate the applicability of the coupled approach, the proposed model was applied and tested in Woomyeon mountain where a catastrophic damage by debris flow occurred and recorded. In comparison with a landslide inventory map, the model simulations resulted in reasonable estimates of the whole mountain hazards caused by slope failures as a sequential process at a regional scale. The coupled analysis proposed in this study appeals that it is important to manage them together because of ...