Click for larger image Credit: COMET/UNIV. OXFORD

Satellite radar images are helping to pin down the origins of the magnitude 6.3 earthquake that devastated the Italian town of L'Aquila on 6 April.

Data taken before and after the quake by the Advanced Synthetic Aperture Radar instrument on the European Space Agency's Earth-monitoring satellite, Envisat, have been used to create an interferogram of the region (pictured). Each coloured fringe corresponds to 28 millimetres of ground motion, and shows that the ground east of the fault (shown) has risen while the basin containing L'Aquila has sunk. Geologists from the Institute for Electromagnetic Sensing of the Environment, part of the Italian National Research Council, and the National Institute of Geophysics and Volcanology in Rome produced the first interferograms of the site.

Richard Walters and John Elliott of the University of Oxford, UK, have now used the same data to model the earthquake, and concluded that the fault line ruptured for about 11 kilometres and slipped by about 80 centimetres.

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