GPS Geodetic Constraints on Caribbean-North America Plate Motion

We describe a model for Caribbean plate motion based on GPS velocities of four sites in the plate interior and two azimuths of the Swan Islands transform fault. The data are well fit by a single angular velocity, with average misfits approximately equal to the 1.5–3.0 mm yr ⁻¹ velocity uncertainties. The new model predicts Caribbean-North America motion ∼65% faster than predicted by NUVEL-1A, averaging 18–20±3 mm yr ⁻¹ (2σ) at various locations along the plate boundary. The data are best fit by a rotation pole that predicts obliquely convergent motion along the plate boundary east of Cuba, but are fit poorly by a suite of previously published models that predict strike-slip motion in this region. The data suggest an approximate upper bound of 4–6 mm yr ⁻¹ for internal deformation of the Caribbean plate, although rigorous estimates await more precise and additional velocities from sites in the plate interior.