Tsunami hazard in the Caribbean: Regional exposure derived from credible worst case scenarios

The present study documents a high tsunami hazard in the Caribbean region, with several thousands of lives lost in tsunamis and associated earthquakes since the XIXth century. Since then, the coastal population of the Caribbean and the Central West Atlantic region has grown significantly and is still growing. Understanding this hazard is therefore essential for the development of efficient mitigation measures. To this end, we report a regional tsunami exposure assessment based on potential and credible seismic and non-seismic tsunamigenic sources. Regional tsunami databases have been compiled and reviewed, and on this basis five main scenarios have been selected to estimate the exposure. The scenarios comprise two Mw8 earthquake tsunamis (north of Hispaniola and east of Lesser Antilles), two subaerial/submarine volcano flank collapse tsunamis (Montserrat and Saint Lucia), and one tsunami resulting from a landslide on the flanks of the Kickʹem Jenny submarine volcano (north of Grenada). Offshore tsunami water surface elevations as well as maximum water level distributions along the shore lines are computed and discussed for each of the scenarios. The number of exposed people has been estimated in each case, together with a summary of the tsunami exposure for the earthquake and the landslide tsunami scenarios. For the earthquake scenarios, the highest tsunami exposure relative to the population is found for Guadeloupe (6.5%) and Antigua (7.5%), while Saint Lucia (4.5%) and Antigua (5%) have been found to have the highest tsunami exposure relative to the population for the landslide scenarios. Such high exposure levels clearly warrant more attention on dedicated mitigation measures in the Caribbean region.