Crust–Uppermost Mantle Structure beneath the Caribbean Region from Seismic Ambient Noise Tomography

Abstract

ABSTRACT We present a new 3D shear velocity model for the crust–uppermost mantle structure beneath the Caribbean region from the surface down to 150 km depth. Our velocity model was derived from joint inversion of group and phase velocity dispersion data obtained from ambient noise and earthquake data. The group and phase dispersion curves estimated from ambient noise were calculated from cross correlation using up to 4 yr of continuous data. Perturbations in group and phase surfaces-wave velocities within a resolution of 1° × 1° show the relevant geotectonic units in the Caribbean plate. Plate boundaries, ocean basins, rises, rifts, and microplates are well defined by shear-wave velocity impedances. The 3D shear-wave velocity inversion along profiles shows the thickening of the crust from the ocean to continental margins. We present a new Moho interface map with depths undulating between 11 and 17 km beneath most parts of the sea and 25–45 km below the continental areas. Low-velocity zones were found in the uppermost mantle indicating a highly laterally heterogeneous area.