Dynamics of Erebus Glacier Tongue

Abstract

Recent measurements conducted on Erebus Glacier Tongue (EGT) have enabled improvements to be made to previous analyses of earlier data (Holdsworth 1974). The use of LANDSAT imagery and controlled aerial photography up to 1978 have enabled glacier flow rates and hence strain-rates to be determined more accurately than before. Re-analysis of the stress and strain-rate data leads to flow law constants which are now more compatible with those of Thomas (1973). The thinner ice appears to be “softer” than the thicker ice. Bending of EGT appears to be the result of current pressure exerted on the south side of the glacier, and computed bending strains seem to account for most of the observed curvature of EGT.Basal ice melting predominates over any possible refreezing; melt rates along the south edge exceed basal melt rates by a factor of 5-10. Short-period, pseudo-elastic deformations occurring in EGT as a result of ocean wave-induced motion may be responsible for continually activating crevasses and producing the apparent “softening” effect in the creep of the thinner ice. Such oscillations may also lead to the calving of EGT although recent observations suggest that a hinge-line calving due to horizontal bending of EGT may be just as likely.