| dc.description.abstract | Typhoon events are often accompanied by short-duration intense rainfall. If the slopes are steep and rich in loose soil, rocks, or colluvium, it is prone to induce significant debris flows and landslides, causing heavy casualties and economic losses. The occurrence of debris flows and landslides is influenced by geology, topography, and the hydrological environment. To assess the affected area of the combined process, the landslide and debris flow requires an integrated modeling framework. This study adopts the physical-based model, which is based on the SHALSTAB model proposed by Montgomery and Dietrich (1994). Our study developed a coupled hydrologic-stability model by changing its assumptions about soil structure and modifying the critical rainfall into the critical humidity. This study assumes a double-layer model incorporating a fractured layer under the soil layer. The failure plane is located at the interface between the soil and fracture layer, and the groundwater is also accumulated at the soil-fracture layer interface. The landslide event induced by Typhoon Saola in Heping Village, Xiulin Township, Hualien County on August 2, 2012, is selected as the study case. The results will compare with the landslide inventory digitized by the post-disaster orthoimage of the Aerial Survey Office (ASO) and will be quantified through two criteria, which are the proportion of correctly predicted affected areas(??) and the overall prediction accuracy(??), and examine the over-predicted or under-predicted of the model through errors of commission(?????) and errors of omission(????). For the landslide timing validation, we use the Major Disaster Event Reportsissued by the Soil and Water Conservation Bureau (SWCB) as the ground truth data for comparison. In the simulation of the debris flow path, the model results show that ?? is 81%, ?? is 94%, ????? is 35% and ???? is 44%. Under different failure scenarios, the single-layer model simulates 22.7% more saturated areas than the double-layer. In landslide timing prediction, the predicted landslide timing of the double-layer model is 61h, which is corresponded with the report. In contrast, the single-layer model predicts the failure 37h earlier than the observation. It can be seen that the addition of the fracture layer not only influences the predicted affected area but also affects the prediction landslide timing. Overall, the research results show that considering the characteristics of fracture flow in the model can indeed improve the model performance and has certain benefits. | en_US |