Measurements of Side-slip at Austerdalsbreen, 1959

Abstract

One of the most interesting problems in the theory of glacier flow concerns the extent to which glaciers slip past the bedrock. The problem is of theoretical interest because, until recently, there was no theory which enabled the amount of this slip to be predicted, and the recent theory of J. Weertman (1957) has still to be tested experimentally. It is also of interest in any consideration of the mechanism of glacial erosion, for clearly a glacier which is stuck fast to its bed will be a less active eroding agent than one which is slipping and carrying with it debris which can scour the bedrock. However, the slip of a glacier over its bed at depth is a difficult quantity to measure, and it is therefore of interest to see how fast glaciers slip relative to the rock in those places where the interface is easily accessible, that is, where the glacier side is sufficiently clear of snow and moraine for the ice-rock contact to be visible from the surface.