An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada
Active-layer detachment slides are locally common on Fosheim Peninsula, Ellesmere Island, where permafrost is continuous, the active layer is 0.5-0.75 m thick, and summer temperatures are unusually high in comparison with much of the Canadian High Arctic. In this paper we report pore-water pressures...
Published in: | Canadian Geotechnical Journal |
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Online Access: | http://dx.doi.org/10.1139/t99-118 http://www.nrcresearchpress.com/doi/pdf/10.1139/t99-118 |
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crcansciencepubl:10.1139/t99-118 2024-06-23T07:50:36+00:00 An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada Harris, Charles Lewkowicz, Antoni G 2000 http://dx.doi.org/10.1139/t99-118 http://www.nrcresearchpress.com/doi/pdf/10.1139/t99-118 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Geotechnical Journal volume 37, issue 2, page 449-462 ISSN 0008-3674 1208-6010 journal-article 2000 crcansciencepubl https://doi.org/10.1139/t99-118 2024-05-24T13:05:50Z Active-layer detachment slides are locally common on Fosheim Peninsula, Ellesmere Island, where permafrost is continuous, the active layer is 0.5-0.75 m thick, and summer temperatures are unusually high in comparison with much of the Canadian High Arctic. In this paper we report pore-water pressures at the base of the active layer, recorded in situ on two slopes in late July and early August 1995. These data form the basis for slope stability analyses based on effective stress conditions. During fieldwork, the factor of safety within an old detachment slide on a slope at Hot Weather Creek was slightly greater than unity. At "Big Slide Creek," on a slope showing no evidence of earlier detachment failures, the factor of safety was less than unity on a steep basal slope section but greater than unity elsewhere. In the upper slope, pore-water pressures were only just subcritical. Sensitivity analyses demonstrate that the stability of the shallow active layer is strongly influenced by changes in soil shear strength. Possible mechanisms for reduction in shear strength through time include weathering of soils and gradual increases in basal active layer ice content. However, we suggest here that soil shearing during annual gelifluction movements is most likely to progressively reduce shear strengths at the base of the active layer from peak values to close to residual, facilitating the triggering of active-layer detachment failures.Key words: detachment slides, Ellesmere Island, pore-water pressures, gelifluction. Article in Journal/Newspaper Arctic Ellesmere Island Fosheim Peninsula Ice Nunavut permafrost Canadian Science Publishing Arctic Canada Ellesmere Island Fosheim Peninsula ENVELOPE(-83.749,-83.749,79.669,79.669) Hot Weather Creek ENVELOPE(-84.466,-84.466,79.935,79.935) Nunavut Canadian Geotechnical Journal 37 2 449 462 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Active-layer detachment slides are locally common on Fosheim Peninsula, Ellesmere Island, where permafrost is continuous, the active layer is 0.5-0.75 m thick, and summer temperatures are unusually high in comparison with much of the Canadian High Arctic. In this paper we report pore-water pressures at the base of the active layer, recorded in situ on two slopes in late July and early August 1995. These data form the basis for slope stability analyses based on effective stress conditions. During fieldwork, the factor of safety within an old detachment slide on a slope at Hot Weather Creek was slightly greater than unity. At "Big Slide Creek," on a slope showing no evidence of earlier detachment failures, the factor of safety was less than unity on a steep basal slope section but greater than unity elsewhere. In the upper slope, pore-water pressures were only just subcritical. Sensitivity analyses demonstrate that the stability of the shallow active layer is strongly influenced by changes in soil shear strength. Possible mechanisms for reduction in shear strength through time include weathering of soils and gradual increases in basal active layer ice content. However, we suggest here that soil shearing during annual gelifluction movements is most likely to progressively reduce shear strengths at the base of the active layer from peak values to close to residual, facilitating the triggering of active-layer detachment failures.Key words: detachment slides, Ellesmere Island, pore-water pressures, gelifluction. |
format |
Article in Journal/Newspaper |
author |
Harris, Charles Lewkowicz, Antoni G |
spellingShingle |
Harris, Charles Lewkowicz, Antoni G An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada |
author_facet |
Harris, Charles Lewkowicz, Antoni G |
author_sort |
Harris, Charles |
title |
An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada |
title_short |
An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada |
title_full |
An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada |
title_fullStr |
An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada |
title_full_unstemmed |
An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada |
title_sort |
analysis of the stability of thawing slopes, ellesmere island, nunavut, canada |
publisher |
Canadian Science Publishing |
publishDate |
2000 |
url |
http://dx.doi.org/10.1139/t99-118 http://www.nrcresearchpress.com/doi/pdf/10.1139/t99-118 |
long_lat |
ENVELOPE(-83.749,-83.749,79.669,79.669) ENVELOPE(-84.466,-84.466,79.935,79.935) |
geographic |
Arctic Canada Ellesmere Island Fosheim Peninsula Hot Weather Creek Nunavut |
geographic_facet |
Arctic Canada Ellesmere Island Fosheim Peninsula Hot Weather Creek Nunavut |
genre |
Arctic Ellesmere Island Fosheim Peninsula Ice Nunavut permafrost |
genre_facet |
Arctic Ellesmere Island Fosheim Peninsula Ice Nunavut permafrost |
op_source |
Canadian Geotechnical Journal volume 37, issue 2, page 449-462 ISSN 0008-3674 1208-6010 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/t99-118 |
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Canadian Geotechnical Journal |
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37 |
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2 |
container_start_page |
449 |
op_container_end_page |
462 |
_version_ |
1802641513974333440 |