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Trench motion-controlled slab morphology and stress variations: Implications for the isolated 2015 Bonin Islands deep earthquake

Yang, Ting and Gurnis, Michael and Zhan, Zhongwen (2017) Trench motion-controlled slab morphology and stress variations: Implications for the isolated 2015 Bonin Islands deep earthquake. Geophysical Research Letters, 44 (13). pp. 6641-6650. ISSN 0094-8276. http://resolver.caltech.edu/CaltechAUTHORS:20170620-080506863

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Abstract

The subducted old and cold Pacific Plate beneath the young Philippine Sea Plate at the Izu-Bonin trench over the Cenozoic hosts regional deep earthquakes. We investigate slab morphology and stress regimes under different trench motion histories with mantle convection models. Viscosity, temperature, and deviatoric stress are inherently heterogeneous within the slab, which we link to the occurrence of isolated earthquakes. Models expand on previous suggestions that observed slab morphology variations along the Izu-Bonin subduction zone, exhibited as shallow slab dip angles in the north and steeper dip angles in the south, are mainly due to variations in the rate of trench retreat from the north (where it is fast) to the south (where it is slow). Geodynamic models consistent with the regional plate tectonics, including oceanic plate age, plate convergence rate, and trench motion history, reproduce the seismologically observed principal stress direction and slab morphology. We suggest that the isolated ~680 km deep, 30 May 2015 M_w 7.9 Bonin Islands earthquake, which lies east of the well-defined Benioff zone and has its principal compressional stress direction oriented toward the tip of the previously defined Benioff zone, can be explained by Pacific slab buckling in response to the slow trench retreat.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/2017GL073989DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2017GL073989/abstractPublisherArticle
ORCID:
AuthorORCID
Yang, Ting0000-0003-2301-2525
Gurnis, Michael0000-0003-1704-597X
Zhan, Zhongwen0000-0002-5586-2607
Additional Information:© 2017 American Geophysical Union. Received 29 APR 2017; Accepted 14 JUN 2017; Accepted article online 19 JUN 2017; Published online 3 JUL 2017. T. Y. benefitted from the discussion with Lingling Ye. We thank two anonymous reviewers for their commentary on the paper. Supported by the NSF under EAR-1247022, EAR-1600956, and EAR-1645775. The Finite element software Citcom used for model calculation can be downloaded from the CIG website https://geodynamics.org/.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR-1247022
NSFEAR-1600956
NSFEAR-1645775
Subject Keywords:trench motion; slab dynamics; deep earthquake; isolated events; nonlinear viscosity; Bonin Islands
Record Number:CaltechAUTHORS:20170620-080506863
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20170620-080506863
Official Citation:Yang, T., M. Gurnis, and Z. Zhan (2017), Trench motion-controlled slab morphology and stress variations: Implications for the isolated 2015 Bonin Islands deep earthquake, Geophys. Res. Lett., 44, 6641–6650, doi:10.1002/2017GL073989
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78358
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Jun 2017 04:36
Last Modified:02 Aug 2017 21:06

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