Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins
Abstract The physics of water flow within and under glacier ice is examined with special reference to the periodic catastrophic outbursts of water (jökulhlaups) from the subglacial lake Grímsvötn, Vatnajökull, Iceland. The lake is sealed until it reaches a critical level which enables it to lift the...
Published in: | Journal of Glaciology |
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Language: | English |
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Cambridge University Press (CUP)
1976
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Online Access: | http://dx.doi.org/10.1017/s002214300001354x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300001354X |
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crcambridgeupr:10.1017/s002214300001354x 2024-06-23T07:53:03+00:00 Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins Nye, J. F. 1976 http://dx.doi.org/10.1017/s002214300001354x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300001354X en eng Cambridge University Press (CUP) Journal of Glaciology volume 17, issue 76, page 181-207 ISSN 0022-1430 1727-5652 journal-article 1976 crcambridgeupr https://doi.org/10.1017/s002214300001354x 2024-06-12T04:04:49Z Abstract The physics of water flow within and under glacier ice is examined with special reference to the periodic catastrophic outbursts of water (jökulhlaups) from the subglacial lake Grímsvötn, Vatnajökull, Iceland. The lake is sealed until it reaches a critical level which enables it to lift the glacier, helped by a hydrostatic cantilever effect. The differential equations for non-steady water flow in a subglacial tunnel are derived and applied to the 1972 Grímsvötn outburst. The discharge: time relation observed during the growth stage, and the abrupt ending of the flood, are both very well accounted for by a theory which is insensitive to the details of the subglacial tunnel system. The steady state, in which an intergranular vein or tunnel is simultaneously melted open by frictional heat and closed by plastic deformation, may be stable or unstable according to the conditions imposed at the ends. This explains why the flow of water in a vein does not normally increase unstably as in a jökulhlaup. An ice-dammed lake does not drain away through the vein system because the driving force on the vein-water is towards the lake rather than away from it. Article in Journal/Newspaper glacier Iceland Journal of Glaciology Vatnajökull Cambridge University Press Vatnajökull ENVELOPE(-16.823,-16.823,64.420,64.420) Dammed Lake ENVELOPE(-68.258,-68.258,68.496,68.496) Journal of Glaciology 17 76 181 207 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract The physics of water flow within and under glacier ice is examined with special reference to the periodic catastrophic outbursts of water (jökulhlaups) from the subglacial lake Grímsvötn, Vatnajökull, Iceland. The lake is sealed until it reaches a critical level which enables it to lift the glacier, helped by a hydrostatic cantilever effect. The differential equations for non-steady water flow in a subglacial tunnel are derived and applied to the 1972 Grímsvötn outburst. The discharge: time relation observed during the growth stage, and the abrupt ending of the flood, are both very well accounted for by a theory which is insensitive to the details of the subglacial tunnel system. The steady state, in which an intergranular vein or tunnel is simultaneously melted open by frictional heat and closed by plastic deformation, may be stable or unstable according to the conditions imposed at the ends. This explains why the flow of water in a vein does not normally increase unstably as in a jökulhlaup. An ice-dammed lake does not drain away through the vein system because the driving force on the vein-water is towards the lake rather than away from it. |
format |
Article in Journal/Newspaper |
author |
Nye, J. F. |
spellingShingle |
Nye, J. F. Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins |
author_facet |
Nye, J. F. |
author_sort |
Nye, J. F. |
title |
Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins |
title_short |
Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins |
title_full |
Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins |
title_fullStr |
Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins |
title_full_unstemmed |
Water Flow in Glaciers: Jökulhlaups, Tunnels and Veins |
title_sort |
water flow in glaciers: jökulhlaups, tunnels and veins |
publisher |
Cambridge University Press (CUP) |
publishDate |
1976 |
url |
http://dx.doi.org/10.1017/s002214300001354x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300001354X |
long_lat |
ENVELOPE(-16.823,-16.823,64.420,64.420) ENVELOPE(-68.258,-68.258,68.496,68.496) |
geographic |
Vatnajökull Dammed Lake |
geographic_facet |
Vatnajökull Dammed Lake |
genre |
glacier Iceland Journal of Glaciology Vatnajökull |
genre_facet |
glacier Iceland Journal of Glaciology Vatnajökull |
op_source |
Journal of Glaciology volume 17, issue 76, page 181-207 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s002214300001354x |
container_title |
Journal of Glaciology |
container_volume |
17 |
container_issue |
76 |
container_start_page |
181 |
op_container_end_page |
207 |
_version_ |
1802644527423422464 |