Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought?
The detachment of large parts of low-angle mountain glaciers resulting in massive ice–rock avalanches have so far been believed to be a unique type of event, made known to the global scientific community first for the 2002 Kolka Glacier detachment, Caucasus Mountains, and then for the 2016 collapses...
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2021
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ftdoajarticles:oai:doaj.org/article:13bc6e6827384e6d8769655e49a86051 2023-05-15T18:32:28+02:00 Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? A. Kääb M. Jacquemart A. Gilbert S. Leinss L. Girod C. Huggel D. Falaschi F. Ugalde D. Petrakov S. Chernomorets M. Dokukin F. Paul S. Gascoin E. Berthier J. S. Kargel 2021-04-01T00:00:00Z https://doi.org/10.5194/tc-15-1751-2021 https://doaj.org/article/13bc6e6827384e6d8769655e49a86051 EN eng Copernicus Publications https://tc.copernicus.org/articles/15/1751/2021/tc-15-1751-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-1751-2021 1994-0416 1994-0424 https://doaj.org/article/13bc6e6827384e6d8769655e49a86051 The Cryosphere, Vol 15, Pp 1751-1785 (2021) Environmental sciences GE1-350 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.5194/tc-15-1751-2021 2022-12-31T06:32:11Z The detachment of large parts of low-angle mountain glaciers resulting in massive ice–rock avalanches have so far been believed to be a unique type of event, made known to the global scientific community first for the 2002 Kolka Glacier detachment, Caucasus Mountains, and then for the 2016 collapses of two glaciers in the Aru range, Tibet. Since 2016, several so-far unrecognized low-angle glacier detachments have been recognized and described, and new ones have occurred. In the current contribution, we compile, compare, and discuss 20 actual or suspected large-volume detachments of low-angle mountain glaciers at 10 different sites in the Caucasus, the Pamirs, Tibet, Altai, the North American Cordillera, and the Southern Andes. Many of the detachments reached volumes in the order of 10–100 million m 3 . The similarities and differences between the presented cases indicate that glacier detachments often involve a coincidental combination of factors related to the lowering of basal friction, high or increasing driving stresses, concentration of shear stress, or low resistance to exceed stability thresholds. Particularly soft glacier beds seem to be a common condition among the observed events as they offer smooth contact areas between the glacier and the underlying substrate and are prone to till-strength weakening and eventually basal failure under high pore-water pressure. Partially or fully thawed glacier bed conditions and the presence of liquid water could thus play an important role in the detachments. Surface slopes of the detached glaciers range between around 10 ∘ and 20 ∘ . This may be low enough to enable the development of thick and thus large-volume glaciers while also being steep enough to allow critical driving stresses to build up. We construct a simple slab model to estimate ranges of glacier slope and width above which a glacier may be able to detach when extensively losing basal resistance. From this model we estimate that all the detachments described in this study occurred due to a basal shear ... Article in Journal/Newspaper The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 15 4 1751 1785 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 A. Kääb M. Jacquemart A. Gilbert S. Leinss L. Girod C. Huggel D. Falaschi F. Ugalde D. Petrakov S. Chernomorets M. Dokukin F. Paul S. Gascoin E. Berthier J. S. Kargel Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
The detachment of large parts of low-angle mountain glaciers resulting in massive ice–rock avalanches have so far been believed to be a unique type of event, made known to the global scientific community first for the 2002 Kolka Glacier detachment, Caucasus Mountains, and then for the 2016 collapses of two glaciers in the Aru range, Tibet. Since 2016, several so-far unrecognized low-angle glacier detachments have been recognized and described, and new ones have occurred. In the current contribution, we compile, compare, and discuss 20 actual or suspected large-volume detachments of low-angle mountain glaciers at 10 different sites in the Caucasus, the Pamirs, Tibet, Altai, the North American Cordillera, and the Southern Andes. Many of the detachments reached volumes in the order of 10–100 million m 3 . The similarities and differences between the presented cases indicate that glacier detachments often involve a coincidental combination of factors related to the lowering of basal friction, high or increasing driving stresses, concentration of shear stress, or low resistance to exceed stability thresholds. Particularly soft glacier beds seem to be a common condition among the observed events as they offer smooth contact areas between the glacier and the underlying substrate and are prone to till-strength weakening and eventually basal failure under high pore-water pressure. Partially or fully thawed glacier bed conditions and the presence of liquid water could thus play an important role in the detachments. Surface slopes of the detached glaciers range between around 10 ∘ and 20 ∘ . This may be low enough to enable the development of thick and thus large-volume glaciers while also being steep enough to allow critical driving stresses to build up. We construct a simple slab model to estimate ranges of glacier slope and width above which a glacier may be able to detach when extensively losing basal resistance. From this model we estimate that all the detachments described in this study occurred due to a basal shear ... |
format |
Article in Journal/Newspaper |
author |
A. Kääb M. Jacquemart A. Gilbert S. Leinss L. Girod C. Huggel D. Falaschi F. Ugalde D. Petrakov S. Chernomorets M. Dokukin F. Paul S. Gascoin E. Berthier J. S. Kargel |
author_facet |
A. Kääb M. Jacquemart A. Gilbert S. Leinss L. Girod C. Huggel D. Falaschi F. Ugalde D. Petrakov S. Chernomorets M. Dokukin F. Paul S. Gascoin E. Berthier J. S. Kargel |
author_sort |
A. Kääb |
title |
Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? |
title_short |
Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? |
title_full |
Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? |
title_fullStr |
Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? |
title_full_unstemmed |
Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? |
title_sort |
sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought? |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-1751-2021 https://doaj.org/article/13bc6e6827384e6d8769655e49a86051 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 15, Pp 1751-1785 (2021) |
op_relation |
https://tc.copernicus.org/articles/15/1751/2021/tc-15-1751-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-1751-2021 1994-0416 1994-0424 https://doaj.org/article/13bc6e6827384e6d8769655e49a86051 |
op_doi |
https://doi.org/10.5194/tc-15-1751-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
4 |
container_start_page |
1751 |
op_container_end_page |
1785 |
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1766216588756779008 |