Figure 1. (a) Present-day plate boundary faults of the Caribbean plate modified from Gordon et al. [1997]. Directions and rates of plate motion relative to the Caribbean plate from DeMets et al. [1996]. EPGFZ is Enriquillo Plantain Garden fault zone. Box shows location of study area (Figure 2). (b) Main tectonic arcs in the Caribbean area, modified from Gordon et al. [1997]. Arrows indicate inferred direction of opening in the Yucatan back arc basin [Rosencrantz, 1990] and the Granada back arc basin [Bird et al., 1993].