Geodynamics and Neotectonics of the Cordillera Septentrional and Samaná Peninsula, Dominican Republic: implications for seismotectonics and seismic hazard assessment

Abstract

The Dominican Republic is exposed to a high seismic hazard due to its geodynamic location between two active margins of oblique convergence. New geodynamic, neotectonic and seismotectonic data of the Cordillera Septentrional and Samaná Peninsula, and also the onshore area of the northern microplate, have allowed the location of the main seismotectonic fault zones. Structural, stratigraphic and morphotectonic information obtained from the fault zones at several scales has allowed us to interpret their kinematics and consistency with the obtained regional stress tensor deduced from dynamic inverse methods. This information complemented by the record of historical seismicity, displacement velocity and seismic parameters of the fault zones has allowed us to evaluate the seismic hazard of the studied area.The method used for the evaluation of the seismic hazard is probabilistic and considers three types of seismic sources: the subduction zone, the main strike-slip fault zones and the areas located between them. This method allows us to calculate the iso-lines of peak ground acceleration (PGA) with a resolution of 0.05º for an exceedance probability of 10% (50 years) and a return period of 475 years. Resulting PGA bands are arranged sub-parallel to the North Hispaniola, Septentrional and Camú Fault Zones, as well as the main ONO-ESE-trending faults systems, detecting a maximum of PGA towards the SE of the modelled area. Consequently, the cities with the lowest seismic hazard are those located towards the NW of the maximum PGA zone.