Iglesias, A. and Clayton, R. W. and Pérez‐Campos, X. and Singh, S. K. and Pacheco, J. F. and García, D. and Valdés‐González, C. (2010) S wave velocity structure below central Mexico using high-resolution surface wave tomography. Journal of Geophysical Research B, 115 . Art. No. B06307. ISSN 0148-0227 http://resolver.caltech.edu/CaltechAUTHORS:20100709-135147262
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Shear wave velocity of the crust below central Mexico is estimated using surface wave dispersion measurements from regional earthquakes recorded on a dense, 500 km long linear seismic network. Vertical components of regional records from 90 well-located earthquakes were used to compute Rayleigh-wave group-velocity dispersion curves. A tomographic inversion, with high resolution in a zone close to the array, obtained for periods between 5 and 50 s reveals significant differences relative to a reference model, especially at larger periods (>30 s). A 2-D S wave velocity model is obtained from the inversion of local dispersion curves that were reconstructed from the tomographic solutions. The results show large differences, especially in the lower crust, among back-arc, volcanic arc, and fore-arc regions; they also show a well-resolved low-velocity zone just below the active part of the Trans Mexican Volcanic Belt (TMVB) suggesting the presence of a mantle wedge. Low densities in the back arc, inferred from the low shear wave velocities, can provide isostatic support for the TMVB.
|Additional Information:||© 2010 American Geophysical Union. Received 26 January 2009; accepted 11 January 2010; published 15 June 2010. This study was supported by the Tectonics Observatory of Caltech and by the PAPIIT‐UNAM project IN104308. MASE was funded by the Gordon and Betty Moore Foundation. We thank E. Debayle and M. Sambridge for providing their tomographic and resolution codes. O. A. Castro kindly assisted us in relocating some of the events used in this study. We thank S. I. Franco‐Sánchez for the help in preparing the last versions of Figures 6 and 7. SSN and C.I.S., I.I., UNAM staff generously provided us seismic data from their networks. We thank all MASE volunteers, most of them undergraduate students. Finally, we thank the JGR Editor and two anonymous reviewers for their comments and suggestions that led to a much improved manuscript. Contribution 91 of the Tectonics Observatory.|
|Group:||Caltech Tectonics Observatory|
|Subject Keywords:||surface wave tomography; structure below central Mexico; MASE|
|Other Numbering System:|
|Official Citation:||Iglesias, A., R. W. Clayton, X. Pérez‐Campos, S. K. Singh, J. F. Pacheco, D. García, and C. Valdés‐González (2010), S wave velocity structure below central Mexico using high‐resolution surface wave tomography, J. Geophys. Res., 115, B06307, doi:10.1029/2009JB006332|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||09 Jul 2010 21:13|
|Last Modified:||26 Dec 2012 12:12|
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