Seismic structure of the crust in the western Dominican Republic

Abstract

The contact between the Caribbean and North American plates is a tectonically complicated boundary where the deformation is accommodated in north and south of Hispaniola by the Enriquillo-Plantain Garden and Septentrional–Oriente Fault Zones (EPGFZ and SOFZ). We present a crustal and tectonic study of the Northeastern Caribbean Plate Boundary from wide-angle seismic data (WAS) acquired during the GEOPRICO-DO (2005) and CARIBE NORTE (2009) surveys, showing two transects crossing, from north to south, North American Plate (NOAM), Bahamas Platform, central Hispaniola and Caribbean Plate (CP). The results presented include two 2-D P wave velocity models of 425 km and 200 km long oriented NNE-SSW and ENE-SSW, respectively, obtained by the travel time forward and inverse modeling of the WAS data. Our study defines that the contact between Bahamas Platform, North American Plate and Hispaniola corresponds to oblique subduction with the Moho dipping 11° in the NNE-SSW direction. Furthermore, in the south, our results reveal the existence of an anomalous deep-reaching zone of lateral velocity variation in the mantle that could be associated with EPGFZ and a possible detached oceanic slab from NOAM that could explain the deep seismicity in the region.