An investigation into the forces that drive ice-shelf rift propagation on the Amery Ice Shelf, East Antarctica

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...

Full description

Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Bassis, JN, Fricker, HA, Coleman, R, Minster, JB
Format: Article in Journal/Newspaper
Language:English
Published: 2008
Subjects:
Online Access:https://eprints.utas.edu.au/7000/
https://eprints.utas.edu.au/7000/1/Bassis_etal_JGlac_2008.pdf
https://doi.org/10.3189/002214308784409116
Description
Summary: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, short-term stresses due to winds and ocean swell may become more important.