Tsunami Risk from a Mentawai Islands Megathrust Earthquake: 2006AGUFM.S31C..07M

John McCloskey, Andrea Antonioli, Alessio Piatanesi, K Sieh, Sandy Steacy, Suleyman S Nalbant, P Dunlop, JianDong Huang, M Cocco, Carlo Giunchi

Research output: Contribution to conferenceAbstract


Interaction stresses from recent great earthquakes on the Sunda Trench subduction zone have made another earthquake, this time under the Mentawai Islands, more likely. The megathrust under Siberut Island has not ruptured since the great 1797 earthquake and may be ripe for triggered failure. Paleogeodetic studies support a range of possible events, the smallest of which would rupture only that part of the megathrust which rupture in 1797 but not in 1833, the largest could propagate southward, breaking the Enganno Island barrier. The practical consequences of these events would depend crucially on their tsunami potential, which in turn depends on details of slip distribution on the future earthquake. Here we employ a Monte Carlo approach to the forward problem and model about 1000 possible earthquakes, calculating the seafloor displacements and tsunami wave height distributions resulting from the most likely 100 or so. Results forecast generally smaller tsunamis compared to those generated by the Sumatra-Andaman earthquake. We show that the Mentawai Islands, on the fore arc high, play a cruical role in moderating the tsunami hazard, reducing the impact of high slip on at intermediate depths on the megathrust and dissipating energy from tsunami waves generated over the trench. These results will help to constrain preparedness strategies around the Indian Ocean and in particular on western Sumatra.
Original languageEnglish
Number of pages1
Publication statusPublished (in print/issue) - 11 Dec 2006
EventAmerican Geophysical Union: Fall Meeting - San Francisco, United States
Duration: 11 Dec 200615 Dec 2006


ConferenceAmerican Geophysical Union
Abbreviated titleAGU
Country/TerritoryUnited States
CitySan Francisco

Bibliographical note



  • Tsunami


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