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Evidence of an upper mantle seismic anomaly opposing the Cocos slab beneath the Isthmus of Tehuantepec, Mexico

Kim, YoungHee and Lim, Hobin and Miller, Meghan S. and Pearce, Fred and Clayton, Robert W. (2014) Evidence of an upper mantle seismic anomaly opposing the Cocos slab beneath the Isthmus of Tehuantepec, Mexico. Geochemistry Geophysics Geosystems, 15 (7). pp. 3021-3034. ISSN 1525-2027. doi:10.1002/2014GC005320.

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Subduction of the Cocos plate beneath southern Mexico is characterized by several unusual features, such as a discontinuous volcanic arc, unusual arc chemistry, and anomalously low topography of Tehuantepec Isthmus. Recent seismic images from both receiver functions and seismic tomography suggest that there may be an additional, opposing structure dipping to the southwest from the Gulf of Mexico, and these images have been previously explained by a southwest-dipping slab. However, standard models of the Caribbean tectonic history do not support this interpretation. To better define the Cocos slab's structure and the possible existence of a structure dipping in the opposite direction, dense seismic data across southern Mexico are used to form high-resolution seismic images, based on the 2-D generalized radon transform method, and to relocate regional earthquakes. Our images show the Cocos plate dipping at 30° to the northeast encounters the anomaly that is dipping in the opposite sense at ∼150 km depth. Relocated seismicity clearly delineates a Wadati-Benioff zone that marks the subducting Cocos plate. A cluster of seismicity also appears at ∼150 km depth which may be related to the subduction of the Tehuantepec ridge and/or to the imaged seismic structure with opposite polarity.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Kim, YoungHee0000-0002-1111-632X
Lim, Hobin0000-0001-7510-4507
Miller, Meghan S.0000-0001-5494-2296
Clayton, Robert W.0000-0003-3323-3508
Additional Information:© 2014 American Geophysical Union. Received 27 FEB 2014; Accepted 5 JUL 2014; Accepted article online 10 JUL 2014; Published online 25 JUL 2014. Y.K. and H.L. were funded by the Korea Meteorological Administration Research and Development Program under Grant CATER-2013-8010. M.S.M. was funded by NSF EAR-1054638. Authors thank entire VEOX team for making the data available. Finally, authors thank the editor and anonymous reviewers for helpful comments, which greatly improved the paper.
Group:Seismological Laboratory
Funding AgencyGrant Number
Korea Meteorological Administration Research and Development ProgramCATER-2013-8010
Issue or Number:7
Record Number:CaltechAUTHORS:20140918-083707405
Persistent URL:
Official Citation:Kim, Y.H., H. Lim, M. S. Miller, F. Pearce, and R. W. Clayton (2014), Evidence of an upper mantle seismic anomaly opposing the Cocos slab beneath the Isthmus of Tehuantepec, Mexico, Geochem. Geophys. Geosyst., 15, 3021–3034, doi:10.1002/2014GC005320
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49805
Deposited By: Tony Diaz
Deposited On:18 Sep 2014 22:43
Last Modified:28 Sep 2022 22:25

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