Geodetic Surveying of Intrusive Events

Northeast Iceland

Abstract

Following an episode in Northeast Iceland known as the “Krafla Rifting Episode” 1975-1981, a transient accerelation of the spreading rate between the North American and Eurasian plates was observed by geodetic surveys 1987-1990 using Global Positioning System (GPS). This post-rifting crustal deformation can be interpreted as the response of the shallow elastic layer to the rifting episode (dyke intrusions) delayed by mechanical coupling with an underlying viscous layer. We also found a smaller amount of radial displacements possibly caused by the inflation of the magma chamber beneath the Krafla Caldera.