Tim Wright of the University of Leeds and his international team of colleagues collected ground- and space-based observations of a widening rift in the Afar Desert of Ethiopia. Between September and October last year, a 60-kilometer-long stretch of rock spread by as much as eight meters. Magma from adjacent volcanoes filled in the bottom part of the rift, creating new continental crust and a dyke of roughly 2.5 cubic kilometers--twice as much material as erupted from Mount St. Helens--more than two kilometers below the surface.
"A lot of ash was thrown up in the air and a lot of cracks appeared in the ground, some of which were more than a meter wide," says team member Cindy Ebinger of the University of London. "The Afar region provides a unique study area for continental breakup and formation of new ocean basins." That is because it is one of the few active rifts on land rather than in the depths of the old oceans. This spreading of the continental crust will continue along the rift, stretching from Lebanon to Tanzania, with the eastern edge of Africa potentially following Madagascar out to sea. A paper presenting the research appears in today's Nature.