Earth Science Frontiers ›› 2023, Vol. 30 ›› Issue (4): 405-417.DOI: 10.13745/j.esf.sf.2023.2.64

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Mechanism of ice avalanche in the Sedongpu sag, Yarlung Zangbo River basin-an experimental study

TANG Minggao(), LIU Xinxin, LI Guang*(), ZHAO Huanle, XU Qiang, ZHU Xing, LI Weile   

  1. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China
  • Received:2022-07-25 Revised:2023-02-03 Online:2023-07-25 Published:2023-07-07


In recent years ice avalanche disasters occur frequently in the Tibetan Plateau and the mechanism of ice avalanche has attracted much attention. In this paper, the evolutionary process and controlling factors of ice avalanche in the Sedongpu sag were investigated via multi-stage imaging analysis. In the mechanistic study, shear strength tests were carried out at different temperatures on two types of ice materials: crystalline ice and ice-rock mixture. The crystalline ice sample was prepared by pressing crushed ices into a mold, and the ice-rock mixture was prepared by pressing crushed ices and slate. Imaging analysis results showed that glaciers with 30° or steeper terrain slopes were prone to ice avalanche while strong near-field earthquakes aggravated glacier deformation/fracture, and climate warming was the main reason for the frequent occurrence of ice avalanches in the Sedongpu sag. In the shear test, the shear stress-shear displacement curves for both materials revealed brittle deformation type, while for polycrystalline ice a “secondary peak” appeared under low temperature conditions, indicating refreezing phenomenon. With increasing temperature, the cohesive strength and internal friction angle of both materials decreased linearly, even at an accelerated pace; whilst at the same temperature, the cohesive strength was less and the internal friction angle was greater for ice-rock mixture than for polycrystalline ice. Thus the likely genetic mechanism of ice avalanche is that the rise of temperature leads to decrease of shear strength of the ice/rock shear sliding zone thus its anti-sliding force to trigger an ice avalanche.

Key words: ice avalanche, genetic mechanism, evolution characteristics, shear test, interpretation of remote sensing, Sedongpu sag

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