Seismotectonics and Crustal Structure in the Southern Dominican Republic Offshore Margin: Implications on the Tsunami Potential

Abstract

Many coastal areas of the southern Dominican Republic experience considerable population pressure accompanied by important economic activity. The southern offshore margin is characterized by significant seismicity and active geological processes. Because of the proximity of the seismogenic and tsunamigenic areas to the coastal regions, large seismic events are likely to result in significant damage. The interpretation of seismotectonic, structural, and morphological data allowed us to characterize the tsunamigenic features. The major tectonic sources involve large shallow faults that are capable of producing earthquakes with magnitudes ranging from Mw7.0 to Mw8.1. These seismic sources could release enough energy to deform and occasionally rupture the seafloor: Muertos frontal thrust, Muertos mega-splay and the Muertos Trough fault zone. In addition, these tectonic sources show significant vertical seafloor deformation with the potential to generate tsunamis. The steeper seafloor slopes show frequent active gravitational processes, but generally have a relatively small size and their tsunamigenic potential is therefore low. However, the Complutense slump is an exception showing ≈30 km3 of mobilized material located along a large active fault. If a similar volume is rapidly mobilized in a single slope failure, it could generate a significant tsunami. The southern coast of the Dominican Republic faces a clear risk due to its proximity to potential tsunamigenic sources (30–50 km), resulting in a very short lead-time for warning. The results of this study provide basic information for future tsunami simulations that ultimately allow practical implementation of tsunami preparedness and protection, and for coastal planning and marine resource use.