Preliminary report on tests of the application of geophysical methods to Arctic ground water problems

Abstract

Seismic refraction and electrical resistivity surveys were made during the summer and fall of 1952 in the Tanana Valley near Fairbanks, Alaska, as part of the studies of the application of geophysical techniques to ground-water problems in Alaska instigated in 1951 by the U.S. Army Engineer Research and Development Laboratories. Work centered around the highway junctions at Fairbanks, Big Delta, and Tok. It was found that both survey methods defined the horizontal extent of the frozen ground and both were capable of determining the depth to the top of the permafrost but neither regularly yielded reliable information on the material beneath the top of the permafrost. The greatest need at present is for a thorough examination of data obtained in the field seasons of 1948 and 1952. Two fundamental theoretical investigations are desirable: (1) examination of the attenuation of longitudinal waves traveling through a thin layer, and (2) further development of the theoretical multilayer resistivity interpretation of problems in which the second layer has a very high resistivity. Further field work should include: (1) tests of the U.S. Geological Survey's new shallow-reflection seismograph; (2) a brief test of electromagnetic equipment; (3) additional resistivity measurements with commutated current; and (4) both seismic and resistivity measurements in areas where the bedrock possesses different physical properties from the schist usually found in interior Alaska. It is doubtful that geophysical techniques are sufficiently developed to be valuable for use by Army personnel in prospecting for ground water in areas of thick permafrost.