Short duration water pressure transients in western Greenland's subglacial drainage system

[...]if slip-induced stress transients are the cause of observed pulses, this implies that local stick-slip behavior at the bed is rare, supporting Kavanaugh's (2009) assertion that frequent pulse behavior may be a characteristic of soft-bedded glaciers and can be revealing of bed conditions. 4...

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Bibliographic Details
Published in:Journal of glaciology 2018-02, Vol.64 (243), p.171-174
Main Authors: MEIERBACHTOL, TOBY W., HARPER, JOEL T., HUMPHREY, NEIL F.
Format: Article
Language:English
Subjects:
Drainage systems
Drilling
Duration
Erosion
Erosion processes
Erosion rates
Glaciers
Hydrostatic pressure
Pressure transducers
Water pressure
Winter
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Summary:[...]if slip-induced stress transients are the cause of observed pulses, this implies that local stick-slip behavior at the bed is rare, supporting Kavanaugh's (2009) assertion that frequent pulse behavior may be a characteristic of soft-bedded glaciers and can be revealing of bed conditions. 4.2 Implications for erosion processes Regardless of their cause, considering that our data support a hard-bedded setting at our study site, then even the infrequent occurrence of pressure pulses may still have implications for bedrock quarrying processes. Through finite element modeling of the stress state in a bedrock step with a water cavity in its lee side, Iverson (1991) showed that a pressure reduction in the cavity removed back-stress on the bedrock lee face, and increased the normal ice pressure on the bedrock just upstream. [...]even rare water pressure deviations at the bed can influence long-term bedrock fracture rates, particularly when such deviations are large. Over time, the accumulated damage facilitated by pulse behavior could therefore provide a mechanism to enhance basal erosion over Greenland's ablation zone; a region where basal erosion rates have recently been estimated to be orders of magnitude greater than previously thought (Cowton and others, 2012).
ISSN:0022-1430
1727-5652
DOI:10.1017/jog.2018.9