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Lower-mantle Substructure Embedded in the Farallon Plate: The Hess Conjugate

Ko, Justin Yen-Ting and Helmberger, Don V. and Wang, Huilin and Zhan, Zhongwen (2017) Lower-mantle Substructure Embedded in the Farallon Plate: The Hess Conjugate. Geophysical Research Letters, 44 (20). pp. 10216-10225. ISSN 0094-8276. doi:10.1002/2017GL075032.

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The morphologies of subducted remnants in the lower mantle are essential to our understanding of the history of plate tectonism. Here we image a high-velocity slab-like (HVSL) anomaly beneath the southeastern U.S. using waveforms from five deep earthquakes beneath South America recorded by the USArray. In addition to travel time anomalies, the multipathing of S and ScS phases at different distances are used to constrain the HVSL model. We jointly invert S and ScS traveltimes, amplitudes, and waveform complexities to produce a best fitting block model characterized by a rectangular shape with a 2.5% S wave velocity increase and tapered edges. While the Farallon slab is expected to dip primarily eastward, the HVSL structure apparently dips 40° to 50° to the SE and appears to be related to the eclogitized Hess conjugate.

Item Type:Article
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URLURL TypeDescription
Ko, Justin Yen-Ting0000-0003-1523-4494
Wang, Huilin0000-0003-3061-0806
Zhan, Zhongwen0000-0002-5586-2607
Additional Information:© 2017 American Geophysical Union. Received 20 JUL 2017; Accepted 17 SEP 2017; Accepted article online 29 SEP 2017; Published online 21 OCT 2017. We thank Nathan Simmons, who provided the newest global model used for the FD simulations, and the IRIS DMC (, which provided the earthquake waveform data used in our study. Suggestions and comments were provided by the Editor (Jeroen Ritsema), a reviewer (Daniel A. Frost), and an anonymous reviewer that helped to improve our manuscript. We also thank Priscilla McLean for her help in preparing this manuscript. This work was supported by the NSF CSEDI program.
Group:Seismological Laboratory
Funding AgencyGrant Number
Subject Keywords:waveform modeling; multi-pathing; Farallon plate; Hess conjugate
Issue or Number:20
Record Number:CaltechAUTHORS:20171002-081952835
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Official Citation:Ko, J. Y.-T., Helmberger, D. V., Wang, H., & Zhan, Z. (2017). Lower mantle substructure embedded in the Farallon Plate: The Hess conjugate. Geophysical Research Letters, 44, 10,216–10,225.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81932
Deposited By: Tony Diaz
Deposited On:02 Oct 2017 17:45
Last Modified:15 Nov 2021 19:47

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