dc.date.accessioned | 2018-01-16T14:39:54Z | |
dc.date.available | 2018-01-16T14:39:54Z | |
dc.date.issued | 2018 | |
dc.identifier.uri | http://hdl.handle.net/10852/59629 | |
dc.description.abstract | We used a finite element model to interpret anti-correlated pressure variations at the base of a glacier to demonstrate the importance of stress redistribution in the basal ice. We first investigated two pairs of load cells installed 20 m apart at the base of the 210 m thick Engabreen glacier in Northern Norway. The load cell data for July 2003 showed that pressurisation of a subglacial channel located over one load cell pair led to anti-correlation in pressure between the two pairs. To investigate the cause of this anti-correlation, we used a full Stokes 3D model of a 210 m thick and 25–200 m wide glacier with a pressurised subglacial channel represented as a pressure boundary condition. The model reproduced the anti-correlated pressure response at the glacier bed and variations in pressure of the same order of magnitude as the load cell observations. The anti-correlation pattern was shown to depend on the bed/surface slope. On a flat bed with laterally constrained cross-section, the resulting bridging effect diverted some of the normal forces acting on the bed to the sides. The anti-correlated pressure variations were then reproduced at a distance >10–20 m from the channel. In contrast, when the bed was inclined, the channel support of the overlying ice was vertical only, causing a reduction of the normal stress on the bed. With a bed slope of 5 degrees, the anti-correlation occurred within 10 m of the channel. The model thus showed that the effect of stress redistribution can lead to an opposite response in pressure at the same distance from the channel and that anti-correlation in pressure is reproduced without invoking cavity expansion caused by sliding. | en_US |
dc.language.iso | en | en_US |
dc.relation.ispartof | Lefeuvre, Pierre-Marie Benoit Émile (2016) Subglacial Processes and Subglacial Hydrology. Doctoral thesis. http://hdl.handle.net/10852/49237 | |
dc.relation.uri | http://hdl.handle.net/10852/49237 | |
dc.rights | Attribution 4.0 International | |
dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | |
dc.title | Stress Redistribution Explains Anti-correlated Subglacial Pressure Variations | en_US |
dc.type | Journal article | en_US |
dc.creator.author | Lefeuvre, Pierre-Marie | |
dc.creator.author | Zwinger, Thomas | |
dc.creator.author | Jackson, Miriam | |
dc.creator.author | Gagliardini, Olivier | |
dc.creator.author | Lappegard, Gaute | |
dc.creator.author | Hagen, Jon Ove | |
dc.identifier.cristin | 1535704 | |
dc.identifier.jtitle | Frontiers in Earth Science | |
dc.identifier.volume | 5 | |
dc.identifier.doi | https://doi.org/10.3389/feart.2017.00110 | |
dc.identifier.urn | URN:NBN:no-62308 | |
dc.type.document | Tidsskriftartikkel | en_US |
dc.type.peerreviewed | Peer reviewed | |
dc.identifier.fulltext | Fulltext https://www.duo.uio.no/bitstream/handle/10852/59629/1/feart-05-00110.pdf | |
dc.type.version | PublishedVersion | |
cristin.articleid | 110 | |