Surface Exploration and Monitoring of Geothermal Activity in the Kverkfjˆll Geothermal Area, Central Iceland

Abstract

The Kverkfjˆll high-temperature area is situated within the Kverkfjˆll central volcano, Central Iceland. The volcano consists of a mountain massif of hyaloclastic rocks, of evolved basaltic composition, and a fissure swarm comprising lava flows, rows of craters and hyaloclastic ridges. The thermal activity of the high-temperature area, is mainly confined to three fields, one in the western part of the Kverkfjˆll mountain massif and two in the eastern part of the complex. Geothermal manifestations consist of fumaroles, mudpots and hot springs and cover some 25 km2. Gas geothermometers indicate subsurface temperatures of about 300?C within the geothermal system. Mercury concentrations in steam range from 70 to 750 ng/kg indicating higher concentrations in fumaroles with higher gas content and higher gas geothermometer temperatures.The geothermal area has been monitored with respect to thermal activity and chemistry for about ten years. No major changes have been observed.