The 2 March 2016 Wharton Basin M_w 7.8 earthquake: High stress drop north-south strike-slip rupture in the diffuse oceanic deformation zone between the Indian and Australian Plates
Abstract
The diffuse deformation zone between the Indian and Australian plates has hosted numerous major and great earthquakes during the seismological record, including the 11 April 2012 M_w 8.6 event, the largest recorded intraplate earthquake. On 2 March 2016, an M_w 7.8 strike-slip faulting earthquake occurred in the northwestern Wharton Basin, in a region bracketed by north-south trending fracture zones with no previously recorded large event nearby. Despite the large magnitude, only minor source finiteness is evident in aftershock locations or resolvable from seismic wave processing including high-frequency P wave backprojections and Love wave directivity analysis. Our analyses indicate that the event ruptured bilaterally on a north-south trending fault over a length of up to 70 km, with rupture speed of ≤ 2 km/s, and a total duration of ~35 s. The estimated stress drop, ~20 MPa, is high, comparable to estimates for other large events in this broad intraplate oceanic deformation zone.
Additional Information
© 2016 American Geophysical Union. Received 6 JUN 2016. Accepted 21 JUL 2016. Accepted article online 25 JUL 2016. Published online 4 AUG 2016. This work made use of GMT and SAC software. We thank M. Cleveland for his help with and use of his relocation software for the aftershock analysis. Gavin Hayes and an anonymous reviewer provided constructive comments on the manuscript. The IRIS DMS data center was used to access the seismic data from Global seismic network and Federation of Digital Seismic Network stations. This work was supported by NSF grant EAR0635570 (T.L.).Attached Files
Published - Lay_et_al-2016-Geophysical_Research_Letters.pdf
Supplemental Material - grl54772-sup-0001-supplementary.docx
Supplemental Material - grl54772-sup-0002-supplementary.mov
Supplemental Material - grl54772-sup-0003-supplementary.mov
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Additional details
- Alternative title
- The 2 March 2016 Wharton Basin Mw 7.8 earthquake: High stress drop north-south strike-slip rupture in the diffuse oceanic deformation zone between the Indian and Australian Plates
- Eprint ID
- 71075
- Resolver ID
- CaltechAUTHORS:20161013-163527423
- EAR-0635570
- NSF
- Created
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2016-10-14Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory