Sumatra plate boundary. Image credit: Caltech's Tectonics ObservatoryDecember 03, 2008
Two large quakes beneath Sumatra in 2007 did not adequately relieve built-up stress, according to a study that includes a JPL researcher and radar data.
For more information, go to the Caltech release at http://mr.caltech.edu/media/Press_Releases/PR13215.html .