Sibling earthquakes generated within a persistent rupture barrier on the Sunda megathrust under Simeulue Island

TitleSibling earthquakes generated within a persistent rupture barrier on the Sunda megathrust under Simeulue Island
Publication TypeJournal Article
Year of Publication2017
AuthorsMorgan PM, Feng L, Meltzner AJ, Lindsey EO, Tsang LLH, Hill EM
JournalGeophysical Research Letters
Volume44
Pagination2159–2166
Date Published03/2017
Abstract

A section of the Sunda megathrust underneath Simeulue is known to persistently halt rupture propagation of great earthquakes, including those in 2004 (Mw 9.2) and 2005 (Mw 8.6). Yet the same section generated large earthquakes in 2002 (Mw 7.3) and 2008 (Mw 7.4). To date, few studies have investigated the 2002 and 2008 events, and none have satisfactorily located or explained them. Using near-field InSAR, GPS, and coral geodetic data, we find that the slip distributions of the two events are not identical but do show a close resemblance and largely overlap. We thus consider these earthquakes “siblings” that were generated by an anomalous “parent” feature of the megathrust. We suggest that this parent feature is a locked asperity surrounded by the otherwise partially creeping Simeulue section, perhaps structurally controlled by a broad morphological high on the megathrust.

DOI10.1002/2016GL071901