ABSTRACT
Geothermal systems that have the potential to provide economically useful heat are located throughout the world in diverse geological settings. Finding them can be as easy as noting the presence of a geyser, a boiling mud pot, or a steaming pool. Indeed, the early development of geothermal power installations commonly occurred in places that had obvious surface manifestations, such as Larderello in Italy and The Geysers in California. However, there are many resources that have little or no surface expression (so-called hidden resources). Over the course of the last few decades, increasingly sophisticated geochemical, geophysical, and statistical techniques have been developed to aid in the discovery, location, and evaluation of geothermal resources. These techniques assist with identifying regions that possess a thermal resource and establishing its magnitude. They are also needed to determine whether there is sufficient permeability to allow fluid flow, and whether there is a high probability that sufficient fluid is present to transfer the heat to the surface. All of these attributes are important for establishing the economic viability of a proposed application.
