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dc.contributor.author
Hooke, Roger L.
dc.contributor.author
Hanson, Brian
dc.contributor.author
Iverson, Neal R.
dc.contributor.author
Jansson, Peter
dc.contributor.author
Fischer, Urs H.
dc.date.accessioned
2021-05-11T06:12:01Z
dc.date.available
2021-05-10T13:32:56Z
dc.date.available
2021-05-11T06:12:01Z
dc.date.issued
1997
dc.identifier.issn
0022-1430
dc.identifier.issn
1727-5652
dc.identifier.other
10.3189/S0022143000002938
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/483473
dc.description.abstract
In order to study, in situ, the rheology of a deforming subglacial till, various instruments were emplaced in till beneath Storglaciären, Sweden. Boreholes were used to gain access to the till beneath about 100m of ice. Tiltmeters provided an estimate of the shear strain rate in the till. Two other instruments yielded measures of till strength. In addition, water pressures were recorded in boreholes and in the till, a computer-controlled distance meter provided an effectively continuous record of the surface velocity and data from frequent surveys of a stake network were used to estimate the mean basal drag, based on a force-balance calculation. Tilt rates varied directly with effective pressure, so decreases in water pressure apparently increased the coupling between the glacier and the bed. Surface speed was either out of phase with tilt or varied independently of tilt. Thus, increases in speed were apparently a consequence either of longitudinal coupling or of reduced coupling between the glacier and the bed; they were not a remit of till deformation! Till strength varied directly with effective pressure, which is consistent with it being a Mohr-Coulomb, or frictional material. The devices measuring till strength are presumed to have been pulled through the till at a speed that varied in phase with the surface speed but till strength did not vary systematically with surface speed. This implies that the residual strength of the till is insensitive to strain rate. Thus, the appropriate constitutive equation for till rheology may be of the form: ε̇ ∝ ekτ where k is a constant. This is consistent with experimental data reported in the geotechnical literature.
en_US
dc.language.iso
en
en_US
dc.publisher
International Glaciological Society
dc.title
Rheology of till beneath Storglaciären, Sweden
en_US
dc.type
Journal Article
ethz.journal.title
Journal of Glaciology
ethz.journal.volume
43
en_US
ethz.journal.issue
143
en_US
ethz.journal.abbreviated
J Glaciol
ethz.pages.start
172
en_US
ethz.pages.end
179
en_US
ethz.publication.place
Cambridge
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02115 - Dep. Bau, Umwelt und Geomatik / Dep. of Civil, Env. and Geomatic Eng.::02611 - V. Wasserbau, Hydrologie u. Glaziologie / Lab. Hydraulics,Hydrology,Glaciology::09599 - Farinotti, Daniel / Farinotti, Daniel
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02115 - Dep. Bau, Umwelt und Geomatik / Dep. of Civil, Env. and Geomatic Eng.::02611 - V. Wasserbau, Hydrologie u. Glaziologie / Lab. Hydraulics,Hydrology,Glaciology::09599 - Farinotti, Daniel / Farinotti, Daniel
en_US
ethz.date.deposited
2021-05-10T13:33:13Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Metadata only
en_US
ethz.rosetta.installDate
2021-05-11T06:12:13Z
ethz.rosetta.lastUpdated
2022-03-29T07:20:22Z
ethz.rosetta.versionExported
true
ethz.COinS
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