RESIST IV ITY METHODS IN GEOTHERMAL PROSPECTING IN ICELAND

• Main Authors: Hjalmar Eyste Insson, Olafur G. Flovenz
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1993
• Subjects: Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.502.6210; http://mtnet.dias.ie/working_group/papers/EMWKSHP_ReviewVolumes/1992Wellington/EysteinssonArnasonFlovenz_1992WellingtonReview_SG_1994.pdf

Abstract. Resistivity techniques have been used successfully to identify and delineate geothermal resources in Iceland. The most frequently used techniques include Schlumberger, central loop TEM and head-on profiling. Geothermal systems in Iceland are located both within and outsite the active volcanic regions. Outsite the active volcanic regions the temperature in the upper most kilometer of the geothermal systems is below 150°C whereas the temperature in the geothermal fields within the active volcanic regions exceeds 200 °C. The resistivity of the rock in geothermal fields located outside the active volcanic regions ranges from about 10 ~m to some hundreds of f~m, and are characterized by considerably ower resistivity than of the surrounding rocks. Most of the geothermal systems within the active volcanic regions, show common resistivity structure with low resistivity of 1-5 f~m surround-ing an inner core of higher esistivity. This increasing resistivity with depth is associated with a change in the conduction mechanism, from interface conduction to electrolyte conduction due to a change in alteration minerals at about 240 ° C. Examples of resistivity surveys of geothermal fields from both outsite and within the active volcanic regions are discussed.