Instabilities on Alpine temperate glaciers: new insights arising from the numerical modelling of Allalingletscher (Valais, Switzerland)
Open access
Date
2012Type
- Journal Article
ETH Bibliography
yes
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Abstract
The processes leading to a glacier instability depend on the thermal properties of the contact between the glacier and its bedrock. Assessing the stability of temperate glacier (i.e. the glacier can slide on its bedrock) remains problematic. In order to scrutinize in more detail the processes governing such "sliding" instabilities, a numerical model designed to investigate gravitational instabilities in heterogeneous media was further developed to account for the presence of water at the interface between the bedrock and the glacier for Allalingletscher. This model made it possible to account for various geometric configurations, interaction between sliding and tension cracking and water flow at the bedrock. We could show that both a critical geometrical configuration of the glacier tongue and the existence of a distributed subglacial drainage network were the main causes of the Allalingletscher catastrophic break-off. Moreover, the analysis of the modelling results diagnosed the phenomenon of recoupling of the glacier to its bed followed by a pulse of subglacial water flow as a potential new precursory sign of the final break-off in 1965. This model casts a gleam of hope for a better understanding of the ultimate rupture process resulting from such glacier sliding instabilities. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000163348Publication status
publishedExternal links
Journal / series
Natural Hazards and Earth System SciencesVolume
Pages / Article No.
Publisher
CopernicusOrganisational unit
03812 - Or, Dani (emeritus) / Or, Dani (emeritus)
03738 - Sornette, Didier (emeritus) / Sornette, Didier (emeritus)
08726 - Funk, Martin (Tit.-Prof.)
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ETH Bibliography
yes
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