Mapping Geothermal Potential in the Western United States

Abstract

The U. S. Geological Survey (USGS) is conducting an updated assessment of geothermal resources in the United States. An important component of the assessment is the estimate of the spatial distribution and quantity of undiscovered geothermal resources. Weights of evidence and logistic regression models have been applied through a Geographic Information System (GIS) framework to produce maps of geothermal favorability. These maps provide the basis for characterizing the undiscovered geothermal resource base and could guide future exploration and land use decisions. A total of 28 weights-of-evidence and logistic regression models were developed using varied evidence layers for heat flow, Quaternary magmatism, Quaternary faulting, seismicity, and tectonic stress. The results highlight and quantify the strong correlation of geothermal systems with active tectonic deformation, magmatism, and elevated heat flow. Regions with significant geothermal potential, but few identified geothermal systems, include northeastern Nevada, western Utah, eastern Oregon, and parts of New Mexico, Colorado, and southern Idaho. Ongoing research is directed towards the transformation of these favorability maps to quantitative estimates of the magnitude of undiscovered geothermal resources.