Measurements of radon concentration in geothermal water have been conducted at the Science Institute since 1977, with interruptions. Originally they were done in cooperation with Egill Hauksson, then at Lamont-Doherty Earth Observatory, later with Páll Theodórsson at the SI. The measurements were primarily aimed at detecting changes of radon in association with earthquakes. Systematic changes were seen in 2000 when large earthquakes hit the region. Instruments are being developed for continuous and automatic monitoring of radon.
Recent publications of the Institute of Earth Sciences on this topic:
Einarsson, P., P. Theodórsson, Á. R. Hjartardóttir, and G. I. Guðjónsson (2008). Radon anomalies associated with the earthquakes sequence in June 2000 in the South Iceland Seismic Zone, Pure appl. geophys. 165, 63-74. PAGEOPH. Topical. "Terrestrial fluids, earthquakes and volcanoes: The Hiroshi Wakita Volume II", eds. Nemesio Perez, Sergio Gurrieri, Chi-Yu King and Yuri Taran, doi:10.1007/s00024-007-0292-6.
Einarsson, P., Theodórsson, P, Hjartardóttir, ÁR, Jónsson, G. & Guðjónsson, G.I. (2007). Radon monitoring programs in the South Iceland Seismic Zone 1977-2006. Proceedings of International Brainstorming Session on Geochemical Precursors for Earthquakes, September 11-13, 2006, Saha Institute of Nuclear Physics & Variable Energy Cyclotron Centre, Kolkata, India. Macmillan India Ltd, p. 3-11.