HR: 1340h
AN: C23A-0978    [Abstracts]
TI: Calving of the Brunt Ice Shelf, the Risk of Losing Halley
AU: * Hayes, K
EM: khay@bas.ac.uk
AB: The British Antarctic Survey base station, Halley is situated on the Brunt Ice Shelf on the eastern edge of the Weddell Sea in West Antarctica. The risk of losing Halley to calving stems mainly from crack extension on the ice shelf or iceberg collision from an advancing ice stream further north, called Stancomb-Wills. The risk of calving will significantly increase as Halley approaches and passes the location of the most recent calving front. Halley is currently only 8km from this calving front and at its present velocity (550m a-1) will reach it in about 14 years. Furthermore, there has been a dramatic slowing down of the ice shelf, from about 750 m a-1 in 1999 to 550m a-1 in 2004, as the ice front wraps itself around a grounded area called McDonald Ice Rumples. The ice shelf is currently slowing at a rate of approximately 40m a-1, the effect of this on the stability of the shelf is as yet unknown. The monitoring programme established through the Lifetime of Halley project provides a means of examining and monitoring the ice shelf movement and fluctuations over both short and long time scales, thus providing a crucial early warning system should a calving event occur. This programme, now in its third year, complements observations already established and improves the overall understanding of the Brunt Ice Shelf in terms of its dynamics, stability and fracture mechanics. The following provides information regarding the behavioural history of the Brunt Ice Shelf, the calving problem and the Lifetime of Halley monitoring programme. Some future work will also be outlined with the ultimate aim of providing an improved understanding of crack propagation.
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting