Abstract: | Precise distance measurements made on four networks of permanent benchmarks situated on the active axes of Iceland during the four-year period 1968–1972 showed that a combination of left-lateral and extensional movement is occurring on the Reykjanes Peninsula in southwest Iceland at a rate of about 9 mm per year. Elsewhere in Iceland, the movements, if they exist, are too small to be detected. Measurements from a geothermal area in southwest Iceland showed also that large horizontal movements occur in the vicinity of producing geothermal wells. |