Rupture characteristics of 28 March 2005 Sumatra earthquake from GPS measurements and its implication for tsunami generation

The great earthquake of 28 March 2005 (Mw 8.6) that occurred off the western coast of Sumatra did not cause a much-anticipated major tsunami, despite its large magnitude and its similarities with the giant 2004 Sumatra–Andaman earthquake. The later earthquake caused a deadly tsunami. Here, we analyse the coseismic displacements estimated from Global Positioning System (GPS) measurements in the Sumatra region, which provide constraints on the rupture characteristics. We suggest that since majority of the slip on rupture of this earthquake occurred under the island belt and under shallow water east of it, it could only cause a minor tsunami.