Crustal and uppermost mantle velocity structure beneath the Cordillera Central and Cordillera Oriental, Dominican Republic

The oblique convergence between the Caribbean and North American plates produces the tectonic complexity of Hispaniola Island. The western region is characterized by high topography bounded by dominantly reverse and oblique-slip faults along the edges of the uplifted mountain ranges, while the eastern part is lower in elevation and no important active faults are identified. This work analyzes the seismic data (Profiles A and D) obtained during the CARIBE NORTE project (2009) in the frame of the current MICROSIS-I (2020-2021-1A4-043) and GEOCIBAO-RS (2023-1-1A4-0627) projects. A seismic array of vertical and three-component land stations registered both profiles along N-S and W-E seismic transects of 425 and 450 km, respectively. The seismic sources used in these lines corresponded to three marine shooting lines (LM1N, LM1S for Profile A and LM4, for Profile D), land borehole explosions 1 Ton (S1, S2, and S3), and one earthquake that occurred during the registering period.

We constrained the seismic structure of the Dominican Republic by the inversion of wide-angle seismic travel-time data for the previous 2D P-wave velocity model of both profiles. The results show marked differences between the western and eastern regions of the island. In the eastern zone, the Moho discontinuity rises to 24 km deep, increasing towards the island's interior with a maximum depth value of approximately 30 km in the west and central part of the transect. A structure dipping 18º towards the eastern interior of Hispaniola Island was identified up to 120 km deep from the analysis and relocation of an earthquake that occurred on April 11, 2009, using the CARIBE NORTE temporary seismic network.