What are believed to be the first satellite synthetic aperture radar (SAR) images of a sub-glacial eruption have been captured by the Canadian Space Agency's RADARSAT at the Grimsvotn volcano in Iceland. The high-resolution images were made in late November 1998 before the eruption, in late December 1998 during the eruption, and in mid-January 1999 after the eruption (Figure 1), all in spite of persistent cloud cover and darkness.
The subglacial eruption, centered within Grimsvotn volcano, occurred between December 18 and 28, 1998. It began at the southern rim of the caldera, in the west-central region of the Vatnajokull ice cap glacier, the largest in Europe with a total area of ∼8300 km2. During the eruption's early stages, five craters were active along an eruptive fissure, extending east-west along the southern caldera rim.