Assessment of the distribution and hazard tendency of debris flows along the Chengdu–Changdu section of the Sichuan–Tibet traffic corridor

This paper presents an analysis of the distribution of various types of debris flows along the traffic artery. By examining the distribution of debris flows, the study found that the most conducive geological and tectonic conditions for debris flow formation are located 5–30 km from the main fault and experience peak ground motion acceleration of 0.15 g or 0.20 g. In the study area, debris flows are primarily concentrated in the plateau mountainous region, where the annual average temperature ranges from 4 to 8 ℃ and the annual average rainfall is less than 1000 mm. The paper further examines four key factors contributing to the hazard tendency of debris flows. It discusses in detail the underlying trends in tectonic activity and climate change and how these factors may impact the hazard tendency of debris flows in the study area. By using fuzzy synthesis method, the paper presents the distribution of debris flow hazard tendency within the study area. The study found that 11.9%, 30.8%, 31.0%, 10.4%, and 15.9% of the total area have very high, high, medium, low, and very low risk of debris flows, respectively. Of the 575 debris flow gullies identified by field investigations, 8%, 39%, 49%, 4%, and 0% were classified as having an extremely high, high, medium, low, and extremely low risk of debris flows, respectively. This indicates that the Sichuan–Tibet traffic corridor will remain a high-risk area for debris flows in the future due to the influence of active faults and climate change.