Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland
During a motion event on Unteraargletscher, Bernese Alps, Switzerland, in spring 1996, surface velocities were measured up to eight times a day at four different locations along the central flowline using global positioning system equipment. In addition, accumulated vertical strains over the uppermo...
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International Glaciological Society
2002
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:38165 2023-05-15T16:57:31+02:00 Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland Gudmundsson, Hilmar 2002 https://nrl.northumbria.ac.uk/id/eprint/38165/ https://doi.org/10.3189/172756502781831043 unknown International Glaciological Society Gudmundsson, Hilmar (2002) Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland. Journal of Glaciology, 48 (163). pp. 566-574. ISSN 0022-1430 F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2002 ftunivnorthumb https://doi.org/10.3189/172756502781831043 2022-09-25T06:09:19Z During a motion event on Unteraargletscher, Bernese Alps, Switzerland, in spring 1996, surface velocities were measured up to eight times a day at four different locations along the central flowline using global positioning system equipment. In addition, accumulated vertical strains over the uppermost 50 and 100 m were measured at a location where the total ice thickness is 260 m. The motion event was accompanied by high horizontal and vertical strain rates as compared to annual mean values. A reversal in strain regime was observed, with horizontal strain rates changing to extension while vertical strain rates became compressive. This strain-rate reversal coincided, within the temporal resolution of the data, with a maximum in vertical ice displacement at the surface.Within a day, variations in vertical strain from 0.04 a−1 to −0.06 a−1 were observed over the uppermost 100 m. Vertical stretching is estimated to have contributed to at least 20% of the anomalous vertical ice movement at the surface. There were significant differences between measured longitudinal strain, averaged over a distance corresponding to a few ice thicknesses, and measured vertical strain. In spring 1997 a similar, but more detailed, set of measurements was collected at the same measuring site, and vertical strain rates were found to vary non-uniformly with depth, with the largest values closest to the surface. Article in Journal/Newspaper Journal of Glaciology Northumbria University, Newcastle: Northumbria Research Link (NRL) Journal of Glaciology 48 163 566 574 |
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Northumbria University, Newcastle: Northumbria Research Link (NRL) |
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ftunivnorthumb |
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topic |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
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F800 Physical and Terrestrial Geographical and Environmental Sciences Gudmundsson, Hilmar Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland |
topic_facet |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
During a motion event on Unteraargletscher, Bernese Alps, Switzerland, in spring 1996, surface velocities were measured up to eight times a day at four different locations along the central flowline using global positioning system equipment. In addition, accumulated vertical strains over the uppermost 50 and 100 m were measured at a location where the total ice thickness is 260 m. The motion event was accompanied by high horizontal and vertical strain rates as compared to annual mean values. A reversal in strain regime was observed, with horizontal strain rates changing to extension while vertical strain rates became compressive. This strain-rate reversal coincided, within the temporal resolution of the data, with a maximum in vertical ice displacement at the surface.Within a day, variations in vertical strain from 0.04 a−1 to −0.06 a−1 were observed over the uppermost 100 m. Vertical stretching is estimated to have contributed to at least 20% of the anomalous vertical ice movement at the surface. There were significant differences between measured longitudinal strain, averaged over a distance corresponding to a few ice thicknesses, and measured vertical strain. In spring 1997 a similar, but more detailed, set of measurements was collected at the same measuring site, and vertical strain rates were found to vary non-uniformly with depth, with the largest values closest to the surface. |
format |
Article in Journal/Newspaper |
author |
Gudmundsson, Hilmar |
author_facet |
Gudmundsson, Hilmar |
author_sort |
Gudmundsson, Hilmar |
title |
Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland |
title_short |
Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland |
title_full |
Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland |
title_fullStr |
Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland |
title_full_unstemmed |
Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland |
title_sort |
observations of a reversal in vertical and horizontal strain-rate regime during a motion event on unteraargletscher, bernese alps, switzerland |
publisher |
International Glaciological Society |
publishDate |
2002 |
url |
https://nrl.northumbria.ac.uk/id/eprint/38165/ https://doi.org/10.3189/172756502781831043 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_relation |
Gudmundsson, Hilmar (2002) Observations of a reversal in vertical and horizontal strain-rate regime during a motion event on Unteraargletscher, Bernese Alps, Switzerland. Journal of Glaciology, 48 (163). pp. 566-574. ISSN 0022-1430 |
op_doi |
https://doi.org/10.3189/172756502781831043 |
container_title |
Journal of Glaciology |
container_volume |
48 |
container_issue |
163 |
container_start_page |
566 |
op_container_end_page |
574 |
_version_ |
1766049069702053888 |