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The North American-Caribbean plate boundary near the islands of Hispaniola and Puerto Rico is a complex region in which strain is accommodated by different modes of deformation. In 2013, 16 broadband stations were deployed in the Dominican Republic to densify the local permanent network. One goal is to combine their data with those from permanent networks in the Caribbean to develop a better understanding of the crust and upper mantle structure in the Greater Antilles. Here we use the records of 204 stations spanning almost 7years of data to obtain group velocity maps. We observe at short periods the contacts between accreted terranes and the igneous provinces of Hispaniola and Puerto Rico, at longer periods the collisional boundary between the buoyant Bahamas Carbonate Platform and Hispaniola, and the transition from Hispaniola's accreted terranes to the faster lithosphere of the Venezuelan Basin and Cayman Trough.

Plain Language Summary The speed of a seismic surface wave varies with its period, and longer-period surface waves are sensitive to deeper structure than shorter-period waves. Since seismic velocity is a property of the medium through which seismic waves travel, variations in wave speeds correspond to variations in physical properties of the subsurface. In this study we create maps of lateral variations in surface wave group velocities across the northeast Caribbean as proxies for variations in material properties. Maps, presented for a range of periods, show, for example, contacts between accreted terranes and igneous provinces in Hispaniola and Puerto Rico and the collisional boundary between the Bahamas Carbonate Platform and Hispaniola. Although the analysis presented here shows different terranes on the islands of Hispaniola and Puerto Rico, offshore features are relatively poorly resolved. For example, better resolution of the Northern Caribbean/North American plate boundary zone, particularly the Bahamas Platform and Cuba, will require denser and more comprehensive station coverage.