R. Michael Senterfit Carl L. Long 1979 <p>Four days were spent collecting 20 audio-magnetotelluric (AMT) soundings in the area of the Ennis Hot Springs, Mont. (fig. 1). These soundings were made to assist in a regional evaluation of the geothermal potential of the Ennis Hot Springs area.</p><p>Scalar resistivities from the data log (table 1) are indicative of thermal water altering the Quaternary alluvium to the southeast. The alteration extends over an area of 1.5 km by 4 km. The geothermal system is probably along a north-south range fault between the Precambrian gneiss and the Tertiary gravels. The scalar resistivities also indicate a northwest trend that may be an intersecting fault. Therefore any geothermal potential would probably be in the area near the existing hot spring, with a possible extent to the northwest of 1 km and to the southeast some 3 km.</p> application/pdf 10.3133/ofr791308 en U.S. Geological Survey Audio-magnetotelluric data log and station-location map for the Ennis Hot Springs area, Montana reports