UZH-Logo

Unraveling driving factors for large rock–ice avalanche mobility


Schneider, D; Huggel, C; Haeberli, W; Kaitna, R (2011). Unraveling driving factors for large rock–ice avalanche mobility. Earth Surface Processes and Landforms, 36:1948-1966.

Abstract

Large rock-ice avalanches have attracted the attention from scientists for decades and some of these events have caused high numbers of fatalities. A relation of rock slope instabilities in cold high mountain areas to climate change is currently becoming more evident and questions about possible consequences and hazard scenarios in densely populated high mountain regions leading beyond historical precedence are rising. For improving hazard assessment of potential rock-ice avalanches, their mobility is a critical factor. In this contribution we try to unravel driving factors for the mobility of large rock-ice avalanches by synthesizing results from physical laboratory experiments and empirical data from 64 rock-ice avalanches with volumes >1x106 m3 from glacierized high mountain regions around the world. We systematically assess the influence of avalanche volume, water and ice content, low-friction surfaces, and topography on the apparent coefficient of friction (as a measure of mobility). In laboratory experiments we found granular ice in the moving mass to reduce bulk friction up to 20% while water led to a reduction around 50% for completely saturated material compared to dry flows. Evidence for the effects of water as a key driving factor to enhance mobility was also found in the empirical data while the influence of the ice content could not be confirmed to be of much relevance in nature. Besides liquefaction, we confirm that mobility increases with volumes and found that frictional surface characteristics such as flow paths over glaciers are also dominant variables determining mass movement mobility. Effects of the topography along the flow path as well as channeling are assumed to be other critical factors. The results provide an empirical basis to roughly account for different path and flow characteristics of large rock-ice avalanches on the way to find appropriate ranges for friction parameters for scenario modeling and hazard assessments.

Large rock-ice avalanches have attracted the attention from scientists for decades and some of these events have caused high numbers of fatalities. A relation of rock slope instabilities in cold high mountain areas to climate change is currently becoming more evident and questions about possible consequences and hazard scenarios in densely populated high mountain regions leading beyond historical precedence are rising. For improving hazard assessment of potential rock-ice avalanches, their mobility is a critical factor. In this contribution we try to unravel driving factors for the mobility of large rock-ice avalanches by synthesizing results from physical laboratory experiments and empirical data from 64 rock-ice avalanches with volumes >1x106 m3 from glacierized high mountain regions around the world. We systematically assess the influence of avalanche volume, water and ice content, low-friction surfaces, and topography on the apparent coefficient of friction (as a measure of mobility). In laboratory experiments we found granular ice in the moving mass to reduce bulk friction up to 20% while water led to a reduction around 50% for completely saturated material compared to dry flows. Evidence for the effects of water as a key driving factor to enhance mobility was also found in the empirical data while the influence of the ice content could not be confirmed to be of much relevance in nature. Besides liquefaction, we confirm that mobility increases with volumes and found that frictional surface characteristics such as flow paths over glaciers are also dominant variables determining mass movement mobility. Effects of the topography along the flow path as well as channeling are assumed to be other critical factors. The results provide an empirical basis to roughly account for different path and flow characteristics of large rock-ice avalanches on the way to find appropriate ranges for friction parameters for scenario modeling and hazard assessments.

Citations

18 citations in Web of Science®
25 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

3 downloads since deposited on 04 Nov 2011
0 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Date:2011
Deposited On:04 Nov 2011 07:59
Last Modified:05 Apr 2016 15:04
Publisher:Wiley-Blackwell
ISSN:0197-9337
Publisher DOI:10.1002/esp.2218
Permanent URL: http://doi.org/10.5167/uzh-50637

Download

[img]
Content: Published Version
Filetype: PDF - Registered users only
Size: 1MB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations