Dynamic hazard assessment of group-occurring debris flows based on a coupled model

Abstract

A scientific hazard zoning of debris flows can ensure that human activities are not performed therein, thereby reducing economic loss as much as possible. In this study, by considering the formation background conditions of mountain hazards and dynamic rainfall conditions, the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model (TRIGRS) and Flow path assessment of gravitational hazards at a Regional scale (Flow-R) are organically combined to establish a new coupled model for debris flow dynamic hazard assessment from the viewpoint of landslides providing the material source of debris flows. The coupled model was employed in Qingping township, Sichuan province of China, which was severely damaged by the “5·12” Wenchuan earthquake in 2008. Evaluation results show that the accuracy of the coupled model is 87.98%, which is significantly higher than that of the static Flow-R model (75.51%). This study not only considers the effect of the formation condition of mountain hazards and rainfall-induced shallow landslides on the source of debris flows, but also realises real-time hazard assessment and prediction of group-occurring debris flows. The coupled model used in this study provides a new perspective and is paramount for improving the accuracy and reliability of debris flow hazard assessment.