Recent D.C. Resistivity Soundings on Swiss Glaciers

Abstract

D.C. resistivity soundings have been carried out on Unteraargletscher at three places for comparison with earlier seismic reflection results. While in two cases a fair agreement was obtained, the third sounding indicated a strong inhomogeneity of the ice, making a reliable interpretation impossible. Using the seismic depths in the interpretation, more reliable values of ice resistivities were obtained. Additional apparent resistivities were measured on ice and firn on Grosser Aletschgietscher, which are discussed together with similar results from the literature. The resistivity values of temperate glaciers observed so far fall in the range from 25 to 120 MΩ.m. and are thus significantly higher than the experimentally determined ultimate value of 5 MΩ.m. reported for extremely pure ice at 0°C. by Eigen and others (1964). The necessary conditions fur successful resistivity soundings are discussed.