Potential geothermal resources in Hawaii: a preliminary regional survey. Phase I, final report

A regional geothermal resource assessment has been conducted for the major islands in the Hawaiian chain. The assessment was made through the compilation and evaluation of the readily accessible geological, geochemical, and geophysical data for the Hawaiian Archipelago that have been acquired during the last two decades. The geologic criteria used in the identification of possible geothermal reservoirs were age and location of most recent volcanism on the island and the geologic structure of each island. The geochemical anomalies used as traces for geothermally altered groundwater were elevated silica concentrations and elevated chloride/magnesium ion ratios. Geophysical data used to identify subsurface structure with possible geothermal potential were aeromagnetic anomalies, gravity anomalies, and higher-than-normal well and basal spring discharge temperatures. Geophysical and geochemical anomalies that may be the result of subsurface thermal effects have been identified on the islands of Hawaii, Maui, Molokai, and Oahu