1. The 2010 Mw7.8 Mentawai earthquake: Very shallow source of a rare tsunami earthquake determined from tsunami field survey and near-field GPS data
- Author
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Bambang W. Suwargadi, Jose C. Borrero, Paramesh Banerjee, Ignatius Ryan Pranantyo, Emma M. Hill, Linlin Li, Kerry Sieh, Zhenhua Huang, Vassilis Skanavis, Costas E. Synolakis, Danny H. Natawidjaja, Pedro Elosegui, Kenneth A. Macpherson, Qiang Qiu, and Hermann M. Fritz
- Subjects
Seismic gap ,Atmospheric Science ,Ecology ,Subduction ,Paleontology ,Soil Science ,Forestry ,Aquatic Science ,Oceanography ,Foreshock ,Tectonics ,Geophysics ,Space and Planetary Science ,Geochemistry and Petrology ,Slow earthquake ,Interplate earthquake ,Earth and Planetary Sciences (miscellaneous) ,Intraplate earthquake ,Tsunami earthquake ,Geology ,Seismology ,Earth-Surface Processes ,Water Science and Technology - Abstract
[1] The Mw 7.8 October 2010Mentawai, Indonesia, earthquake was a“tsunami earthquake,” a rare type of earthquake that generates a tsunami much larger than expected based on the seismicmagnitude.Itproducedalocallydevastatingtsunami,withrunupcommonlyinexcess of 6 m. We examine this event using a combination of high-rate GPS data, from instruments located on the nearby islands, and a tsunami field survey. The GPS displacement time series are deficient in high-frequency energy, and show small coseismic displacements ( 16 m. Our modeling results show that the combination of the small GPS displacements and large tsunami can only be explained by high fault slip at very shallow depths, far from the islands and close to the oceanic trench. Inelastic uplift of trench sediments likely contributed to the size of the tsunami. Recent results for the 2011 Mw 9.0 Tohoko-Oki earthquake have also shown shallow fault slip, but the results from our study, which involves a smaller earthquake, provide much stronger constraints on how shallow the rupture can be, with the majority of slip for the Mentawai earthquake occurring at depths of
- Published
- 2012
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