The present Arizona geothermal energy program was initiated in response to prior geothermal research and reconnaissance programs conducted primarily under the aegis of the federal government. The initial program was extremely limited in scope, but expansion during the past year to six months has been both rapid and continuing. Early on the program was expanded to include the entire state of Arizona. During the period covered by this report, February 1 to April 30, 1978, a third geologist, James C. Witcher, joined the professional staff, and William L. Weibel began as a half-time graduate assistant. Two projects were completed during this quarter. The chapters in this report, Preliminary Map - Geothermal Energy Resources of Arizona by W. R. Hahman , Sr. and Thermal Gradient Anomalies in Southern Arizona by Salvatore Giardina, Jr. and J. N. Conley, detail the results. Following these are project reports on continuing phases of the overall program. Report contains preliminary geothermal resource map of Arizona; geothermal well temperatures, and thermal gradient models for multiple locations in Arizona, and a ranking of geothermal resources. Also, a Landsat lineament map of Arizona.

The Department of Energy funded reconnaissance geothermal exploration in the State of Arizona between May, 1979 and August, 1982. During that time geologists of the Arizona Bureau of Geology and Mineral Technology were able to measure temperatures in over 100 domestic and irrigation wells and mineral test holes. Thirteen holes were drilled solely for the purpose of obtaining gradient or heat flow information. The temperature measurements were made using a portable temperature logging system that consists of a thermistor mounted on the end of lightweight cable, which is carried on a light aluminum reel. The thermistor resistance is measured by a digital meter supplied by rechargeable batteries. Resistance values were converted into temperature for each reading by using tables constructed from thermistor temperature calibration.