Electrical Resistivity Survey of the Pilgrim Springs Geothermal Area, Alaska

Abstract

Pilgrim Springs is located on the Seward Peninsula about 50 miles north of Nome, Alaska. This paper presents a case history of the use of electrical resistivity to delineate a geothermal reservoir and for drilling recommendations. Pilgrim Springs water, being saline, has an electrical resistivity value of 1-m, providing an ideal contrast for resistivity definition of the reservoir. In 1979 several deep Schulumberger and co-linear dipole-dipole surveys were run in and near the 1.5 km2 thaw window. The results suggest that there is a pancake-shaped reservoir near the surface, approximately 50 m thick, which has the shape of the thaw window but is thicker and deeper to the north under the Pilgrim river. The conduit is suspected to be a small feature which is difficult to find under the near surface, low resistivity reservoir.