A Hydrogeochemical Analysis of Geothermal Resources in the State of Hawaii

The University of Hawaii at Manoa conducted a Play Fairway Analysis of the state of geothermal potential for the islands. Phase I included the aggregation of all existing geologic, geophysical and geochemical data available. A probability model incorporating heat, fluid, and permeability was then created to assess the probability of viable geothermal development. Phase II is the focus of this paper, with new data collection as the goal for this funding period. The Play Fairway Project collected new geothermal groundwater data from 60 wells and 1 spring across the State of Hawaii. Geochemical geothermal indicators used previously in Hawaii, and around the world, were investigated for the newly acquired data in Phase II. These indicators include groundwater temperature, chloride:magnesium ratios, sulfate:chloride ratios, and silica concentrations. All chemical analyses were collected by ... the Play Fairway team and analyzed at various labs at the University of Hawaii at Manoa. Of the ten target areas identified for Phase II, two of the sites provide encouraging groundwater geochemical results for potential geothermal resources. These sites include the Southwest Rift Zone of Haleakala, Maui, and the Palawai Basin, Lanai. Multiple geothermal indicators have been observed in these areas and, therefore, provide encouragement to further explore for subsurface heat. Further investigation is recommended in these target areas through geological, geophysical, and geochemical exploration.

The Hawaii Play Fairway project was funded by the U.S. Department of Energy Geothermal Technologies Office, and the Hawaii Groundwater and Geothermal Resources Center (Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa) executed the project. For more information, go to HGGRC's website that is linked in the resources.