A 3-D shear velocity model of the southern North American and Caribbean plates from ambient noise and earthquake tomography

© Author(s) 2015. Seismic data come from the Mexican National Seismological Service (NSSM), and from the networks CI, CU, G, GE, II, IU, LI, NR, OV, TA and US through the IRIS Consortium. We acknowledge C. Valdés, A. Cárdenas, C. Cárdenas, I. Rodríguez, J. Pérez, J. Estrada, and S. I. Franco for providing NSSM data. The maps and graphs were drawn with the Generic Mapping Tools (Wessel and Smith, 1998). Funds provided by the REPSOL CO-DOS project supported B. Gaite. This is a contribution of the Team Consolider-Ingenio 2010 TOPO-IBERIA (CSD2006-00041). We thank D. García and A. Ugalde for their useful comments for improving this manuscript. We also are grateful to Taka’aki Taira and two anonymous reviewers for their constructive and helpful suggestions for enhancing the paper.
We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh waves to invert for the 3-D shear-wave velocity structure (5–70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita–Marathon–Sonora orogeny front on the crustal seismic structure of the NAM plate. A new imaged feature is the low crustal velocities along the USA-Mexico border. The model also shows a break of the east–west mantle velocity dichotomy of the NAM and CAR plates beneath the Isthmus of the Tehuantepec and the Yucatan Block. High upper-mantle velocities along the Mesoamerican Subduction Zone coincide with inactive volcanic areas while the lowest velocities correspond to active volcanic arcs and thin lithospheric mantle regions.
Team Consolider-Ingenio 2010 TOPO-IBERIA
REPSOL
Depto. de Física de la Tierra y Astrofísica
Fac. de Ciencias Físicas
TRUE
pub