HR: 0800h
AN: C41A-0037    [Abstracts]
TI: Calving of Talyor Glacier, Dry Valleys, Antarctica
AU: * Carmichael, J D
EM: joshuadc@u.washington.edu
AF: University of Washington Department of Earth and Space Sciences, Johnson Hall 070 Box 351310 4000 15th Avenue NE, Seattle, WA 98195-1310, United States
AU: Pettit, E C
EM: epettit@ess.washington.edu
AF: University of Washington Department of Earth and Space Sciences, Johnson Hall 070 Box 351310 4000 15th Avenue NE, Seattle, WA 98195-1310, United States
AU: Creager, K C
EM: kcc@ess.washington.edu
AF: University of Washington Department of Earth and Space Sciences, Johnson Hall 070 Box 351310 4000 15th Avenue NE, Seattle, WA 98195-1310, United States
AU: Hallet, B
EM: hallet@ess.washington.edu
AF: University of Washington Department of Earth and Space Sciences, Johnson Hall 070 Box 351310 4000 15th Avenue NE, Seattle, WA 98195-1310, United States
AB: Calving of tide-water glaciers has received considerable attention, with seismic arrays in Alaska, Greenland, and Antarctica devoted to their observation. In these environments, ice cliffs are directly coupled to oceanic temperatures. The land-based polar glaciers of the McMurdo Dry Valleys in Antarctica represent a simpler environment unaffected directly by water contact where other factors can be isolated. In particular, summer calving events of Taylor Glacier are observed to consist of precursory activity including crack growth, cliff overhang, and active seismicity at least 1 hour before collapse. We propose that collapse occurs only after a stress threshold has been crossed, evident from ‘pre-calving' of ice from the cliff base 1-3 days prior to the major event. We provide photographic, seismic, and temperature data to illustrate the thermal and stress landscape for land-based calving of polar glaciers.
UR: http://earthweb.ess.washington.edu/~joshuadc/
DE: 0720 Glaciers
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 3025 Marine seismics (0935, 7294)
DE: 3260 Inverse theory
DE: 5462 Polar regions
SC: Cryosphere [C]
MN: 2007 Fall Meeting