Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis
We have obtained common offset, common midpoint (CMP) and borehole vertical (VRP) ground-penetrating radar profiles close to the margin of Falljökull, a small, steep temperate valley glacier situated in southeast Iceland. Velocity analysis of CMP and VRP surveys provided a four-layered velocity mode...
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ftnerc:oai:nora.nerc.ac.uk:20052 2023-05-15T16:21:40+02:00 Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis Murray, Tavi Stuart, Graham W. Fry, Matt Gamble, Nicola H. Crabtree, Mike D. 2000 http://nora.nerc.ac.uk/id/eprint/20052/ http://www.ingentaconnect.com/content/igsoc/jog/2000/00000046/00000154/art00004 unknown Murray, Tavi; Stuart, Graham W.; Fry, Matt; Gamble, Nicola H.; Crabtree, Mike D. 2000 Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis. Journal of Glaciology, 46 (154). 389-398. https://doi.org/10.3189/172756500781833188 <https://doi.org/10.3189/172756500781833188> Glaciology Publication - Article PeerReviewed 2000 ftnerc https://doi.org/10.3189/172756500781833188 2023-02-04T19:32:39Z We have obtained common offset, common midpoint (CMP) and borehole vertical (VRP) ground-penetrating radar profiles close to the margin of Falljökull, a small, steep temperate valley glacier situated in southeast Iceland. Velocity analysis of CMP and VRP surveys provided a four-layered velocity model. This model was verified by comparison between the depths of englacial reflectors and water channels seen in borehole video, and from the depths of boreholes drilled to the bed. In the absence of sediment within the glacier ice, radar velocity is inversely proportional to water content. Using mixture models developed by Paren and Looyenga, the variation of water content with depth was determined from the radar velocity profile. At the glacier surface the calculated water content is 0.23−0.34% (velocity 0.166 m ns−1), which rises sharply to 3.0−4.1% (velocity 0.149 m ns−1) at 28 m depth, interpreted to be the level of the piezometric surface. Below the piezometric surface the water content drops slowly to 2.4−3.3% (velocity 0.152 m ns−1) until ∼102 m depth where it falls to 0.09−0.14% (velocity 0.167 m ns−1). The water content of the ice then remains low to the glacier bed at about 112 m. These results suggest storage of a substantial volume of water within the glacier ice, which has significant implications for glacier hydrology, ice rheology and interpretations of both radar and seismic surveys Article in Journal/Newspaper glacier Iceland Journal of Glaciology Natural Environment Research Council: NERC Open Research Archive Paren’ ENVELOPE(163.156,163.156,62.416,62.416) Falljökull ENVELOPE(-16.770,-16.770,63.976,63.976) Journal of Glaciology 46 154 389 398 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Glaciology |
spellingShingle |
Glaciology Murray, Tavi Stuart, Graham W. Fry, Matt Gamble, Nicola H. Crabtree, Mike D. Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis |
topic_facet |
Glaciology |
description |
We have obtained common offset, common midpoint (CMP) and borehole vertical (VRP) ground-penetrating radar profiles close to the margin of Falljökull, a small, steep temperate valley glacier situated in southeast Iceland. Velocity analysis of CMP and VRP surveys provided a four-layered velocity model. This model was verified by comparison between the depths of englacial reflectors and water channels seen in borehole video, and from the depths of boreholes drilled to the bed. In the absence of sediment within the glacier ice, radar velocity is inversely proportional to water content. Using mixture models developed by Paren and Looyenga, the variation of water content with depth was determined from the radar velocity profile. At the glacier surface the calculated water content is 0.23−0.34% (velocity 0.166 m ns−1), which rises sharply to 3.0−4.1% (velocity 0.149 m ns−1) at 28 m depth, interpreted to be the level of the piezometric surface. Below the piezometric surface the water content drops slowly to 2.4−3.3% (velocity 0.152 m ns−1) until ∼102 m depth where it falls to 0.09−0.14% (velocity 0.167 m ns−1). The water content of the ice then remains low to the glacier bed at about 112 m. These results suggest storage of a substantial volume of water within the glacier ice, which has significant implications for glacier hydrology, ice rheology and interpretations of both radar and seismic surveys |
format |
Article in Journal/Newspaper |
author |
Murray, Tavi Stuart, Graham W. Fry, Matt Gamble, Nicola H. Crabtree, Mike D. |
author_facet |
Murray, Tavi Stuart, Graham W. Fry, Matt Gamble, Nicola H. Crabtree, Mike D. |
author_sort |
Murray, Tavi |
title |
Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis |
title_short |
Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis |
title_full |
Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis |
title_fullStr |
Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis |
title_full_unstemmed |
Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis |
title_sort |
englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis |
publishDate |
2000 |
url |
http://nora.nerc.ac.uk/id/eprint/20052/ http://www.ingentaconnect.com/content/igsoc/jog/2000/00000046/00000154/art00004 |
long_lat |
ENVELOPE(163.156,163.156,62.416,62.416) ENVELOPE(-16.770,-16.770,63.976,63.976) |
geographic |
Paren’ Falljökull |
geographic_facet |
Paren’ Falljökull |
genre |
glacier Iceland Journal of Glaciology |
genre_facet |
glacier Iceland Journal of Glaciology |
op_relation |
Murray, Tavi; Stuart, Graham W.; Fry, Matt; Gamble, Nicola H.; Crabtree, Mike D. 2000 Englacial water distribution in a temperate glacier from surface and borehole radar velocity analysis. Journal of Glaciology, 46 (154). 389-398. https://doi.org/10.3189/172756500781833188 <https://doi.org/10.3189/172756500781833188> |
op_doi |
https://doi.org/10.3189/172756500781833188 |
container_title |
Journal of Glaciology |
container_volume |
46 |
container_issue |
154 |
container_start_page |
389 |
op_container_end_page |
398 |
_version_ |
1766009661171957760 |