Fig. 1. Bathymetric and tectonic map of the Puerto Rico and Virgin Islands area. Striped area near eastern Hispaniola, Puerto Rico and the Virgin Islands represents the PRVI platform of Oligocene to Pliocene age. Puerto Rico¯Hispaniola microplate is bounded by the Puerto Rico trench, the Anegada Passage fault zone and the Muertos trough and continues westward to central Hispaniola. Bathymetric map with contour interval of 500 m is based on an integration of EW96-05 Hydrosweep bathymetric data, ETOPO-5 digital terrain map, and digitized National Ocean Survey bathymetric maps compiled by
Mercado (1994). Box shows location of study area in Fig .2. The offshore edge of the PRVI platform, shown by solid line, is interpreted from EW96-05 and Gulf seismic lines and MR-1 sidescan data. Arrow shows direction and rate of Grand Turk on the North America plate relative to Isabela on Puerto Rico from Dixon et al. (1998). Key to abbreviations: NPRSFZ=North Puerto Rico Slope fault zone, SPRSFZ=South Puerto Rico Slope fault zone, SFZ=Septentrional fault zone (from Grindlay et al., 1997).