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The June 2010 Nicobar Earthquake: Fault Reactivation on the Subducting Oceanic Plate

Rajendran, K and Andrade, V and Rajendran, CP (2011) The June 2010 Nicobar Earthquake: Fault Reactivation on the Subducting Oceanic Plate. In: Bulletin of the Seismological Society of America, 101 (5). pp. 2568-2577.

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The similar to 1300-km-long rupture zone of the 2004 Andaman-Sumatra megathrust earthquake continues to generate a mix of thrust, normal, and strike-slip faulting events. The 12 June 2010 M(w) 7.5 event on the subducting plate is the most recent large earthquake on the Nicobar segment. The left-lateral faulting mechanism of this event is unusual for the outer-rise region, considering the stress transfer processes that follow great underthrusting earthquakes. Another earthquake (M(w) 7.2) with a similar mechanism occurred very close to this event on 24 July 2005. These earthquakes and most of their aftershocks on the subducting plate were generated by left-lateral strike-slip faulting on north-northeast-south-southwest oriented near-vertical faults, in response to north-northwest-south-southeast directed compression. Pre-2004 earthquake faulting mechanisms on the subducting oceanic plate are consistent with this pattern. Post-2004, left-lateral faulting on the subducting oceanic plate clusters between 5 degrees N and 9 degrees N, where the 90 degrees E ridge impinges the trench axis. Our study observes that the subducting plate off the Sumatra and Nicobar segments behaves similarly to a chip of the India-Australia plate, deforming in response to a generally northwest-southeast oriented compression, an aspect that must be factored into the plate deformation models.

Item Type: Journal Article
Publication: Bulletin of the Seismological Society of America
Publisher: Seismological Society of America
Additional Information: Copyright of this article belongs to Seismological Society of America.
Date Deposited: 04 Nov 2011 07:29
Last Modified: 04 Nov 2011 07:29
URI: http://eprints.iisc.ac.in/id/eprint/41637

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