Fault-dominated deformation in an ice dam during annual filling and drainage of a marginal lake

Walder, J. S.; Trabant, D. C.; Cunico, M.; Anderson, S. P.; Anderson, R. S.; Fountain, A. G.; Malm, A.

Abstract:

Ice-dammed Hidden Creek Lake, Alaska, USA, outbursts annually in about 2-3 days. As the lake fills, a wedge of water penetrates beneath the glacier, and the surface of this ‘ice dam‘ rises; the surface then falls as the lake drains. Detailed optical surveying of the glacier near the lake allows characterization of ice-dam deformation. Surface uplift rate is close to the rate of lake-level rise within about 400 m of the lake, then decreases by 90% over about 100 m. Such a steep gradient in uplift rate cannot be explained in terms of ice-dam flexure. Moreover, survey targets spanning the zone of steep uplift gradient move relative to one another in a nearly reversible fashion as the lake fills and drains. Evidently, the zone of steep uplift gradient is a fault zone, with the faults penetrating the entire thickness of the ice dam. Fault motion is in a reverse sense as the lake fills, but in a normal sense as the lake drains. As the overall fault pattern is the same from year to year, even though ice is lost by calving, the faults must be regularly regenerated, probably by linkage of surface and bottom crevasses as ice is advected toward the lake basin.

Genre:

Article

ProdID:

70027352

Citation Author:

Walder, J. S.; Trabant, D. C.; Cunico, M.; Anderson, S. P.; Anderson, R. S.; Fountain, A. G.; Malm, A.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

178

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Annals of Glaciology

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

Fault-dominated deformation in an ice dam during annual filling and drainage of a marginal lake; 2005; Article; Journal; Annals of Glaciology; Walder, J. S.; Trabant, D. C.; Cunico, M.; Anderson, S. P.; Anderson, R. S.; Fountain, A. G.; Malm, A.