Electrical resistivity studies on the Athabasca Glacier, Alberta, Canada

The use of electrical methods for measuring ice t hi ckness a nd properties on t he Athabasca Glacier , Alberta, Canada, ha s been st udied by the U.S. Geological Survey. Two m et hods for measuring resistivity were tried: (1) a conventional r esistivity m ethod in w hi ch cUlTent was introdu ced galvanically into t he glacier t hro ugh electrodes, and (2) the other an elec t romagnetic method in which a wire loop la id on the ice was used to induce current flow. Resul ts of the galvanic measurements showed large variations in the resistivity of t he ice; in a surfa ce laye r se vera l t ens of fee t t hi ck the res is tivi ty is betwee n 0.3 and 1.0 megohm-meters, a nd under this layer, t he resist ivity of the ice is more t han 10 mego h m-meters. The resisti vit y of the s urface ice is d etermin ed by i ts water content rather tha n by molecula r reson a nce loss. The ice ha d no effect on the mu t ual couplin g m eas ureme nts in t he fr equ ency range fr o m 100 to J 0,000 cy cles per second . As a con sequ ence t he electrom ag netic d ata could be in terpreted simply in terms of ice t hi ckn ess and bedrock r esi tivity.