Heterogeneity of Strain Rate and the Location of Fracture Events Leading to Iceberg Calving, Columbia Glacier, Alaska.
Abstract
Calving of icebergs from the termini of tidewater glaciers is conventionally analyzed based on a model of detachment of blocks at the boundary of a uniform body of ice. However, this simple view may not be correct. Geostatistical analysis of terrestrial and aerial photogrammetric observations at Columbia Glacier in 1999 shows that strain rates measured on short baselines at many different locations within a few km of the terminus are best correlated at separation distances of ~ 200-300 m. Thus, strain near the terminus is not homogeneous but occurs in discrete 'blocks', which suggests that the disaggregation of continuous ice into individual blocks (icebergs) may occur upstream of the terminus. The possibility of full-thickness fracture upstream from the glacier terminus raises questions about the bulk properties of ice in the terminus region, such as whether the formation of internal voids has a significant influence on bulk density and what factors other than fracture determine the position of the terminus.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2001
- Bibcode:
- 2001AGUFMIP21A0673P
- Keywords:
-
- 1827 Glaciology (1863);
- 1863 Snow and ice (1827)