Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/104649
Title: The 2012 Mw 8.6 Wharton Basin sequence: a cascade of great earthquakes generated by near-orthogonal, young, oceanic mantle faults
Authors: Hill, Emma Mary
Yue, Han
Barbot, Sylvain
Lay, Thorne
Tapponnier, Paul
Hermawan, Iwan
Hubbard, Judith
Banerjee, Paramesh
Feng, Lujia
Natawidjaja, Danny
Sieh, Kerry
Keywords: DRNTU::Science::Geology
Issue Date: 2015
Source: Hill, E. M., Yue, H., Barbot, S., Lay, T., Tapponnier, P., Hermawan, I., et al. (2015). The 2012 Mw 8.6 Wharton Basin sequence: A cascade of great earthquakes generated by near-orthogonal, young, oceanic mantle faults. Journal of geophysical research: solid earth, 120(5), 3723-3747.
Series/Report no.: Journal of geophysical research: solid earth
Abstract: We improve constraints on the slip distribution and geometry of faults involved in the complex, multisegment, Mw 8.6 April 2012 Wharton Basin earthquake sequence by joint inversion of high-rate GPS data from the Sumatran GPS Array (SuGAr), teleseismic observations, source time functions from broadband surface waves, and far-field static GPS displacements. This sequence occurred under the Indian Ocean, ∼400 km offshore Sumatra. The events are extraordinary for their unprecedented rupture of multiple cross faults, deep slip, large strike-slip magnitude, and potential role in the formation of a discrete plate boundary between the Indian and Australian plates. The SuGAr recorded static displacements of up to ∼22 cm, along with time-varying arrivals from the complex faulting, which indicate that the majority of moment release was on young, WNW trending, right-lateral faults, counter to initial expectations that an old, lithospheric, NNE trending fracture zone played the primary role. The new faults are optimally oriented to accommodate the present-day stress field. Not only was the greatest moment released on the younger faults, but it was these that sustained very deep slip and high stress drop (>20 MPa). The rupture may have extended to depths of up to 60 km, suggesting that the oceanic lithosphere in the northern Wharton Basin may be cold and strong enough to sustain brittle failure at such depths. Alternatively, the rupture may have occurred with an alternative weakening mechanism, such as thermal runaway.
URI: https://hdl.handle.net/10356/104649
http://hdl.handle.net/10220/25977
ISSN: 2169-9313
DOI: 10.1002/2014JB011703
Rights: © 2015 American Geophysical Union. This paper was published in Journal of Geophysical Research: Solid Earth and is made available as an electronic reprint (preprint) with permission of American Geophysical Union. The paper can be found at the following official DOI: [http://dx.doi.org/10.1002/2014JB011703]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:EOS Journal Articles

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