Mw 8.6 Sumatran earthquake of 11 April 2012: rare seaward expression of oblique subduction

Geology
By: , and 

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Abstract

The magnitude 8.6 and 8.2 earthquakes off northwestern Sumatra on 11 April 2012 generated small tsunami waves that were recorded by stations around the Indian Ocean. Combining differential travel-time modeling of tsunami waves with results from back projection of seismic data reveals a complex source with a significant trench-parallel component. The oblique plate convergence indicates that ~20-50 m of trench-parallel displacement could have accumulated since the last megathrust earthquake, only part of which has been taken up by the Great Sumatran fault. This suggests that the remaining trench-parallel motion was released during the magnitude 8.6 earthquake on 11 April 2012 within the subducting plate. The magnitude 8.6 earthquake is interpreted to be a result of oblique subduction as well as a reduction in normal stress due to the occurrence of the Sumatra-Andaman earthquake in 2004.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Mw 8.6 Sumatran earthquake of 11 April 2012: rare seaward expression of oblique subduction
Series title Geology
DOI 10.1130/G33783.1
Volume 41
Issue 3
Year Published 2013
Language English
Publisher Geological Society of America
Publisher location Boulder, CO
Contributing office(s) Pacific Coastal and Marine Science Center
Description 4 p.
First page 319
Last page 322
Online Only (Y/N) N
Additional Online Files (Y/N) N