The hydrothermal system associated with the Kilauea East Rift Zone, Hawaii

Abstract

In 1976, a deep research well, named HGP-A, was drilled on the lower southeast flank of Kilauea volcano. The well encountered subsurface temperatures in excess of 350 C and was capable of producing approximately 49 tonnes per hour of steam and brine. A 3 MWe wellhead generator was installed on HGP-a in 1981 and has been in nearly continuous operation for approximately four years. Analysis of the chemistry of the discharge fluids during this period has shown that the hydrothermal system associated with the Kilauea east rift zone (KERZ) is in many respects similar to those found at active seafloor spreading ridges and to the land-based hydrothermal system found on the Reykjanes peninsula in Iceland. Fluid chemistry changes that have occured during the four-year production period have also yielded substantial insight into the temporal aspects of basalt-seawater interaction that occur in the high temperature hydrothermal system present on Kilauea's southeast flank.