Geothermal exploration in the Hveragerdi-Graendalur area, SW-Iceland

Abstract

Geothermal activity is considerable in the Hveragerdi central volcano, chiefly in the western and southern parts. Geothermal mapping in the scale of 1:10,000 involved the mapping and description of hydrothermal phenomena of this area. A general description of geothermal manifestations in the area is given. The geothermal activity is divided into groups and sub-groups. Geothermal activity is mainly related to fractures and faults and these, together with thick loose sediments and landslides, define the geothermal hydrological features at the surface. The characteristics of the manifestations are very similar throughout the area. Therefore, only two detailed figurative descriptions are presented and one of these is described in detail. A detailed soil temperature survey was done in a selected part of the area to determine the lateral extent of an inferred fracture. Also, the energy content of several hot springs was determined with flow measurements. As a conclusion to this report, a hydro geothermal model of the area is proposed, indicating a recharge to the west of the study area. The steam heats the cold ground water producing hot springs at lower topographical levels and steaming ground and solfataras higher up.