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Structure of central and southern Mexico from velocity and attenuation tomography

Chen, Ting and Clayton, Robert W. (2012) Structure of central and southern Mexico from velocity and attenuation tomography. Journal of Geophysical Research B, 117 (9). B09302. ISSN 0148-0227. doi:10.1029/2012JB009233.

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The 3D V_p, V_p/_Vs, P- and S-wave attenuation structure of the Cocos subduction zone in Mexico is imaged using earthquakes recorded by two temporary seismic arrays and local stations. Direct P wave arrivals on vertical components and direct S wave arrivals on transverse components from local earthquakes are used for velocity imaging. Relative delay times for P and PKP phases from teleseismic events are also used to obtain a deeper velocity structure beneath the southern seismic array. Using a spectral-decay method, we calculate a path attenuation operator t^* for each P and S waveform from local events, and then invert for 3D spatial variations in attenuation (Q_p^(−1) and Q_s^(−1)). Inversion results reveal a low-attenuation and high-velocity Cocos slab. The slab dip angle increases from almost flat in central Mexico near Mexico City to about 30° in southern Mexico near the Isthmus of Tehuantepec. High attenuation and low velocity in the crust beneath the Trans-Mexico Volcanic Belt correlate with low resistivity, and are probably related to dehydration of the slab and melting processes. The most pronounced high-attenuation, low-V_p and high-V_p/V_s anomaly is found in the crust beneath the Veracruz Basin. A high-velocity structure dipping into the mantle from the side of Gulf of Mexico coincides with a discontinuity from a receiver functions study, and provides an evidence for the collision between the Yucatán Block and Mexico in the Miocene.

Item Type:Article
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URLURL TypeDescription
Chen, Ting0000-0002-9599-871X
Clayton, Robert W.0000-0003-3323-3508
Additional Information:© 2012 American Geophysical Union. Received 13 February 2012; accepted 20 July 2012; published 5 September 2012. This study was supported by the Gordon and Betty Moore Foundation through the Tectonics Observatory at Caltech and NSF grant EAR0609707. Contribution 91 from the Caltech Tectonics Observatory. We would like to acknowledge Victor Hugo Espindola Castro for providing the SSN catalog. We thank Donna Eberhart-Phillips and Egill Hauksson for the help with the simul2000 package. We also thank Brandon Schmandt and Andreas Rietbrock for helpful discussions. Finally, we thank Editor Robert Nowack and two anonymous reviewers for helpful comments which improved the manuscript.
Group:Caltech Tectonics Observatory, Seismological Laboratory, Division of Geological and Planetary Sciences
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Gordon and Betty Moore FoundationUNSPECIFIED
Caltech Tectonic ObservatoryUNSPECIFIED
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Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory91
Issue or Number:9
Record Number:CaltechAUTHORS:20121002-130315621
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Official Citation:Chen, T. and R. W. Clayton (2012), Structure of central and southern Mexico from velocity and attenuation tomography, J. Geophys. Res., 117, B09302, doi:10.1029/2012JB009233.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34633
Deposited By: Ruth Sustaita
Deposited On:03 Oct 2012 15:05
Last Modified:09 Nov 2021 23:09

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