A coordinated exploration program for geothermal sources on the island of Hawaii

Abstract

Staff members of the Hawaii Institute of Geophysics carried out an exploration program for geothermal sources on the island of Hawaii by using all relevant geophysical and geochemical methods. Infrared scanning aerial surveys followed by reconnaissance-type electrical surveys and group noise surveys narrowed down the promising area to the east rift of Kilauea. The surveys carried out over the east rift included magnetic, gravity, and electrical surveys by various methods: microearthquake, surveillance, temperature profiling of wells, and chemical analysis of water samples. Aeromagnetic, regional gravity, and crustal seismic refraction data were available in published literature. A model of the thermal structure of the east rift was put together to account for the data. The dike complex, through which magma from the central vent of Kilauea travels literally occupies a zone-3-km wide extending from 1-km to 5-km depth. On the south side of the dike complex, there may be a self-sealing geothermal reservoir where groundwater heated by the dike complex is trapped. Not all of the dike complex is hot; hot sections seem to occur in patches.