Geothermal resource assessment of the United States

Geothermal resource assessment is the broadly based appraisal of the quantities of heat that might be extracted from the earth and used economically at some reasonable future time. In the United States, the Geological Survey is responsible for preparing geothermal assessments based on the best available data and interpretations. Updates are required every few years owing to increasing knowledge, enlarging data base, improving technology, and changing economics. Because geothermal understanding is incomplete and rapidly evolving, the USGS complements its assessments with a broad program of geothermal research that includes (1) study of geothermal processes on crustal and local scales, (2) regional evaluations, (3) intensive study of type systems before and during exploitation (4) improvement of exploration techniques, and (5) investigation of geoenvironmental constraints. ?? 1978 Birkha??user Verlag.