| Abstract |
Although a general association of high-temperature geothermal sites and the structural controls provided by faults is evident in the spatial patterns of the western Great Basin, the ages of these faults are poorly known. In this study, we utilize low-sun-angle aerial photography together with field investigations to characterize the age and recency of faulting associated with selected geothermal sites. Although many Quaternary-age faults are distributed across the western Great Basin, nearly all high-temperature sites are spatially associated with Holocene (<10-13 ka) faults. Preliminary results show that of a total of 37 high-temperature sites, 31 sites occur directly on, or in close proximity, to seismically active Holocene faults. Five of these sites are on faults that are structurally related to historical surface ruptures produced by large magnitude earthquakes. New Holocene fault traces have been detected at several sites, including sites in the Needle Rocks, Empire, and Kyle thermal areas. Further work is being conducted on other similar sites, but these preliminary results suggest that the age of faulting, in particular the occurrence of Holocene activity on the fault, is an indicator of recent levels of crustal strain release and may provide an exploration tool in assessing geothermal potential along a given fault structure. |