ABSTRACT
During the early years of exploring for geothermal energy, drilling of areas displaying obvious geothermal surface manifestations, such as hot springs, mudpots, fumaroles, and even geysers, was the primary exploration tool. Some of the resulting wells, however, produced only for short periods-the actual source of the geothermal energy, in such circumstances, being largely missed. Moreover, the geothermal surface features that sparked the initial interest may have been compromised or even destroyed as a result of drilling. To avoid such occurrences, minimize the cost and amount of drilling, and maximize chances of success, an exploration strategy has developed that involves the following components and usually in the following order:
1. Review of existing information in the literature, much of which is now available online
2. Satellite remote sensing studies, including interferometric synthetic aperture radar (InSAR)
3. Airborne photographic and light detection and ranging (LiDAR) surveys 4. Ground-based geologic studies
5. Geochemical and hydrologic studies 6. Geophysical studies (gravity, magnetic, electrical resistivity, and tempera-
ture/heat ow)
Some of these steps are typically combined or take place concurrently for the sake of expediency and the synergy that results by workers from different disciplines sharing collected information as the work proceeds. Close collaboration is typical in the case for eld geologic and geochemical/hydrologic studies. Results of geologic and geochemical studies are helpful to determine the type and location of geophysical techniques that might be most useful for helping delineate prospective geothermal targets.
