The hazard assessment of glacial lake debris flow: A case study on Dongcuoqu, Luolong County, Tibet

Abstract

The development and outbursts of glacial lake debris flow pose threats to downstream infrastructures. Thus, rational assessment of its potential hazards is necessary to mitigate geological hazards along the Sichuan–Tibet railway lines. In this paper, we used logistic regression models and Rapid Mass Movement Simulation methods to assess the multiyear dynamic evolutionary characteristics and outburst risks of the glacial lake and to conduct numerical simulation of the debris flow process. The adopted methodology used remote sensing images from the Landsat 1-Landsat 8 series for the period 1973–2018, combined with the pieces of information of the geological expedition in the glacial lake Dongcuoqu, Luolong County, Tibet, China. The results revealed that the probability of collapse risk of the Dongcuoqu glacial lake dam was 0.39, and its risk extent reached level I, which indicates medium hazardousness and severe loss. The debris flow process simulation comprises of four stages: initiation, acceleration, deceleration, and termination. The outburst floods flow through the proposed location of the Sichuan–Tibet railway. Specifically, the flow velocity in the vicinity of the Luolong station of nearly 5 m/s, which poses a significant threat to the safe construction of the railway. In the flood and non-flood periods, the change in the amount of snow and ice melt was distinctive, and the maximum storage capacities of the glacial lake during these periods were 82 × 106 m3 and 60.1 × 106 m3, respectively. These findings suggest that the assessment results can be used as an excellent reference for the reduction of the construction risk of the proposed Sichuan–Tibet railway under disaster stress in glacial lake outburst hazard areas.