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Abstract

ABSTRACT. For three field seasons (2002/03, 2004/05, 2005/06) we have deployed a network of GPS
receivers and seismometers around the tip of a propagating rift on the Amery Ice Shelf, East Antarctica.
During these campaigns we detected seven bursts of episodic rift propagation. To determine whether
these rift propagation events were triggered by short-term environmental forcings, we analyzed
simultaneous ancillary data such as wind speeds, tidal amplitudes and sea-ice fraction (a proxy variable
for ocean swell). We find that none of these environmental forcings, separately or together, correlated
with rift propagation. This apparent insensitivity of ice-shelf rift propagation to short-term environmental
forcings leads us to suggest that the rifting process is primarily driven by the internal
glaciological stress. Our hypothesis is supported by order-of-magnitude calculations that the
glaciological stress is the dominant term in the force balance. However, our calculations also indicate
that as the ice shelf thins or the rift system matures and iceberg detachment becomes imminent, shortterm
stresses due to winds and ocean swell may become more important.

Item Type:	Article
Authors/Creators:	Bassis, JN and Fricker, HA and Coleman, R and Minster, JB
Keywords:	ice-shelf rift propagation, Amery Ice Shelf, East Antarctica, glaciology
Journal or Publication Title:	Journal of Glaciology
ISSN:	0022-1430
DOI / ID Number:	https://doi.org/10.3189/002214308784409116
Additional Information:	© 2008 International Glaciological Society
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