Geodetic Constraints on Deformation and Earthquake Focal Mechanisms in the Dominican Republic

Abstract

The island of Hispaniola, home to the Dominican Republic and Haiti, lies near the boundary between the Caribbean and North American plates. The interior of the Caribbean plate has most recently been estimated to move 18–20 mm/yr to the east-northeast, implying convergence between Hispaniola/Puerto Rico and the oceanic lithosphere of the North American Plate. In recent geologic history, Hispaniola has been subjected to a block rotation. Due to rotation, deformation has been occurring along the northern edge of the island and may be caused from the left-lateral, strike-slip faults to the north and subduction to the east. Using GIPSY-OASIS II, 39 three-component, continuous global positioning system (GPS) stations located across the northeastern Caribbean region are being processed to determine the relative motion of the Dominican Republic with respect to the surrounding region.

GPS data has been collected from the beginning of 2012 to the present. The GPS data will provide estimates of the overall direction and rate of movement of Hispaniola, as well as elucidate deformation within the island. Due to the island's block rotation, velocity vectors are expected to show slower movement to the northwest on the western side and faster northwest-directed movement on the eastern side of Hispaniola. It is likely that Hispaniola's two major east-west trending transform fault systems (Septentrional in the north and the Enriquillo Plantain Garden in the south) will influence the pattern of velocities as well. In addition, high sample rate GPS data will be used to resolve the fundamental ambiguity between nodal planes found with first motions at seismic stations.

AAPG Datapages/Search and Discovery Article #90219 © 2015 GCAGS, Houston, Texas, September 20-22, 2015