This project aims to develop a technique for estimating the subglacial effective pressure (N), a crucial parameter in calculating glacial motion, which is challenging to measure in the field. To accomplish this, we will test a theory of seismic-wave propagation that links N to subglacial conditions, using a large-diameter ring-shear device to shear temperate ice over a range of known till types at controlled N values. The device will be equipped with an acoustic signal generating/sensing system to measure the seismic reflection amplitude of the ice-bed interface, enabling us to directly relate reflection amplitudes to N in a situation where porosity and grain-size distribution are known. If successful, this novel technique could significantly enhance our comprehension of subglacial hydrology and the connection between ice flow and subglacial effective pressure..

This project is ramping up. More to come soon!