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Published March 31, 2006 | public
Journal Article

Deformation and Slip Along the Sunda Megathrust in the Great 2005 Nias-Simeulue Earthquake

Abstract

Seismic rupture produced spectacular tectonic deformation above a 400-kilometer strip of the Sunda megathrust, offshore northern Sumatra, in March 2005. Measurements from coral microatolls and Global Positioning System stations reveal trench-parallel belts of uplift up to 3 meters high on the outer-arc islands above the rupture and a 1-meter-deep subsidence trough farther from the trench. Surface deformation reflects more than 11 meters of fault slip under the islands and a pronounced lessening of slip trenchward. A saddle in megathrust slip separates the northwestern edge of the 2005 rupture from the great 2004 Sumatra-Andaman rupture. The southeastern edge abuts a predominantly aseismic section of the megathrust near the equator.

Additional Information

© 2006 American Association for the Advancement of Science. Received 14 November 2005; accepted 20 January 2006. This research was supported by the NSF, the Gordon and Betty Moore Foundation, and the Indonesian International Joint Research Program (RUTI). The National Geographic Channel and The Discovery Channel provided partial helicopter support. The captains and crews of Derazona Helicopters, the Mentawai Indah, the Saraina, and the Sariman Jadi provided expert transportation in the air and on the sea. Thanks to M. Chlieh, M. Tobita, and M. Meiner for helpful discussions and to J. Giberson and S. Healy for assistance with spatial data. Finally, we thank the people in the earthquake-affected region for their hospitality and willingness to share their observations. This is Caltech Tectonics Observatory contribution number 29.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023