Distribution of slip in the 2005 (Briggs et al.2006) and 2007 (Konca et al.2008) earthquakes. The grey curve north of Simeulue Island is the southern limit of the rupture of the M9.1 2004 earthquake which propagated for 1500 km north to the Andaman Islands (not shown here). Epicentres of the 2004, 2005 and 2007 earthquakes are shown (stars, NEIC), along with approximate rupture areas for the 1797 (purple) and 1833 (cyan) events (after Natawidjaja et al.2006), and surface traces of the trench (blue) and the Great Sumatran Fault (red).