Refining Caribbean Plate Dynamics: Insights from GPS and InSAR Data

The plate boundary between the Caribbean and North American plates exhibits a striking-complexity and significant width with multiple microplates moving relative to each other, resulting in a significant seismic hazard on the island of Hispaniola. This region has experienced several major earthquakes in recent decades, particularly along the left-lateral fault systems of the Enriquillo-Plantain Garden (EPGF) and Septentrional-Oriente faults. These fault systems accomodate the eastward motion of the Caribbean plate relative to the North American plate at a rate of approximately 20 mm/year. The oblique convergence observed northeast of Hispaniola adds to the complexity of this plate boundary and its distribution among the different fault systems across the Island is currently not fully understood. Geological, seismic, and geodetic studies have suggested the existence of multiple blocks within the island of Hispaniola and while some are well established, others remain hypothetical.

In this work, we propose a new kinematic block model based on an updated GPS velocity field combined with interferometric synthetic aperture radar (InSAR) velocity fields. Deformation rates within the island reveal significant differential motion, particularly between the Gonâve and Hispaniola microblocks, indicating internal deformation that is not accounted for in current rigid block models.

We propose a new model of Caribbean plate dynamics in the vicinity of Hispaniola and provide critical insights for understanding seismic hazards in this tectonically active region.