Sumatran Paleoseismic Study
Large sections of the Sunda megathrust have failed progressively over the past decade in an extraordinary earthquake sequence.
One question of great humanitarian and scientific importance is how the remaining un-ruptured and under-ruptured patches might fail in coming decades. We use annually banded coral microatolls, which preserve precise information about past relative sea levels, to deduce tectonic histories centuries into the past. We continue this work above the 2004, 2005, and 2007 rupture patches—from Simeulue to the Mentawai Islands—to resolve lingering questions and write up results supporting the particularly high hazards we infer for the near future.
Paleoseismologic and coral data are extremely valuable to implement tsunami and earthquake preparedness and mitigation plans in the region. One major achievement was the study of the 2010 Mentawai earthquake that produced an oversized tsunami compared to its magnitude (Mw 7.8). Modelling of the generated tsunami helped constrain the basic fault model parameters. It was demonstrated that a large amount of slip occurred in the young, soft sediments of the shallow megathrust which was previously thought to be an aseismic area.
- Source model of the 2009 Mw 7.6 Padang intraslab earthquake and its effect on the Sunda megathrust. Geophysical Journal International. 190, 1710-1722. (2012).
- An ancient shallow slip event on the Mentawai segment of the Sunda megathrust, Sumatra. Journal of Geophysical Research. 117, (2012).
- Persistent termini of 2004- and 2005-like ruptures of the Sunda megathrust. Journal of Geophysical Research. 117, (2012).
- Earthquake supercycles inferred from sea-level changes recorded in the corals of West Sumatra. Science. 322, 1674-8. (2008).