Satellite radar interferometry 1993-1999 suggests deep accumulation of magma near the crust-mantle boundary at the Krafla volcanic system, Iceland

Deep magma accumulation near the crust-mantle boundary (21 km depth) at the Krafla volcanic system is suggested from InSAR observations. A best fit model, derived from four interferograms covering 1993-1999, comprises an opening dike, representing plate spreading and post-rifting deformation, and two Mogi sources. A Mogi source deflating at a rate of similar to0.3 x 10(6) m(3)/yr coincides with the shallow Krafla magma chamber while a deeper inflating Mogi source, further north, at 21 km depth, inflates at a rate of similar to26 x 10(6) m(3)/yr. The inflating source is at or near the crust-mantle boundary as identified by seismic studies and is interpreted as accumulating magma.