Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published April 2009 | Published + Supplemental Material
Journal Article Open

Tomography and thermal state of the Cocos plate subduction beneath Mexico City

Abstract

The geometry and thermal state of the subducting Cocos plate beneath Mexico City has been enigmatic because of the absence of a deep Wadati‐Benioff zone. We present a tomographic image of the slab based on inversion of 8869 teleseismic P wave travel times measured on a portable broadband seismic network. The images combined with receiver function analysis show that the slab runs flat from the coast to near Mexico City, where it dives into the mantle just before the Trans‐Mexican Volcanic Belt with a dip of ∼75°. It continues down to a depth of ∼500 km at a distance of 400 km from the trench, where the tomography reveals that the dipping portion ends. As well as standard block tomography, we invert the travel time residuals for the parameters of a thermal slab model and find a slab thickness of 40 km that is consistent with the (15 Ma) age of the Cocos plate. The combination of a young hot plate and truncation at depth can explain the lack of deep seismicity due to high temperatures and lower negative buoyancy compared with an older, thicker, nontruncated plate.

Additional Information

© 2009 American Geophysical Union. Issue Online: 28 April 2009; Version of Record online: 28 April 2009; Manuscript accepted: 18 February 2009; Manuscript revised: 24 December 2008; Manuscript received: 27 August 2008. This work was supported by the Tectonics Observatory at Caltech, the Center for Embedded Network Sensors (CENS) at UCLA, NSF award EAR0609707, PAPIITUNAM projects IX120004 and IN119505‐3, and UC MEXUS project 04105384. The MASE experiment was funded by the Gordon and Betty Moore Foundation. Contribution 90 from the Tectonics Observatory. We thank the numerous volunteers for their many hours of field work. We also thank Luca Ferrari and another anonymous reviewer for their comments improving the article.

Attached Files

Published - 2008JB006039.pdf

Supplemental Material - jgrb15939-sup-0001-t01.txt

Files

jgrb15939-sup-0001-t01.txt
Files (1.2 MB)
Name Size Download all
md5:9767e7815f5396526242ef2a01b1c9fc
281 Bytes Preview Download
md5:f639949ca609341b5fb34db869c0e408
1.2 MB Preview Download

Additional details

Created:
August 21, 2023
Modified:
October 23, 2023