Analyzing the Characteristics of Glacial Debris Flow Activity in Parlung Tsangpo Basin, Tibet

Abstract

Parlung Tsangpo, which has a complex geological structure, active neotectonic movement, special hydrometeorological conditions and frequent glacier activity, has become the most dangerous segment of the Sichuan-Tibet highway due to the destruction caused by large-scale glacier debris flows. Evaluating the activity of glacier debris flow gullies is important for forecasting, assessing, and mitigating debris flows. The longitudinal profile of a debris flow valley is a fundamental morphological condition, and together with the rainfall and related hydraulic conditions, all three factors contribute to the initiation and transportation of glacial debris flows. To resolve the problems, such as the complexity of determination research and difficulty of data collection in the evaluation of debris flow gullies, the distribution characteristics of glacial debris flows are analyzed based on the statistical data in the study area. Meanwhile, an effective and convenient method for quantitatively analyzing the evolution stage and activity degree of glacier debris flow gullies is discussed. In this method, an index expressing the shape of the valley’s longitudinal profile is used to link the excess entropy of the geomorphic system with the evolution stage for debris flow gullies. Then, the new evaluation standard for gully evolution can provide a quick activity assessment for debris flow-related early warning systems in the marine glacial area.KeywordsGlacial debris flowShape of longitudinal profileExcess entropyActivity