Strain-rate estimates for crevasse formation at an alpine ice divide: Mount Hunter, Alaska
Crevasse initiation is linked to strain rates that range over three orders of magnitude (0.001 and 0.163 a–1) as a result of the temperature-dependent nonlinear rheological properties of ice and from water and debris inclusions. Here we discuss a small cold glacier that contains buried crevasses at...
| Published in: | Annals of Glaciology |
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| Main Authors: | , , , , , |
| Format: | Text |
| Language: | unknown |
| Published: |
Dartmouth Digital Commons
2013
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| Subjects: | |
| Online Access: | https://digitalcommons.dartmouth.edu/facoa/461 https://doi.org/10.3189/2013AoG63A266 |
| Summary: | Crevasse initiation is linked to strain rates that range over three orders of magnitude (0.001 and 0.163 a–1) as a result of the temperature-dependent nonlinear rheological properties of ice and from water and debris inclusions. Here we discuss a small cold glacier that contains buried crevasses at and near an ice divide. Surface-conformable stratigraphy, the glacier’s small size, and cold temperatures argue for limited rheological variability at this site. Surface ice-flow velocities of (1.2–15.5) ???????? 0.472 m a–1 imply classic saddle flow surrounding the ice divide. Numerical models that incorporate field-observed boundary conditions suggest extensional strain rates of 0.003–0.015 a–1, which fall within the published estimates required for crevasse initiation. The occurrence of one crevasse beginning at 50 m depth that appears to penetrate close to the bed suggests that it formed at depth. Field data and numerical models indicate that a higher interior stress at this crevasse location may be associated with steep convex bed topography; however, the dynamics that caused its formation are not entirely clear. |
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