(a) Horizontal and (b) vertical GPS (red) and GIA model predictions (green) velocity field, plotted on the InSAR velocity. GPS velocities are relative to the ITRF08 Eurasian fixed reference frame. Positive InSAR velocities indicate movement towards the satellite. The error ellipses on the GPS give the 95% confidence region. The inset in panel a) shows the outlines of Iceland and the red box shows the outlines of panels a) and b). The map, including the inset, was created using the public domain Generic Mapping Tools software package.