Tsunami hazard in the Anguilla Bank Archipelago, Lesser Antilles: historical data, fault characterization and numerical simulation

This study assesses earthquake-related tsunami hazard across the Anguilla bank through numerical simulations of selected seismic rupture scenarios. Population growth and urban concentration in low-elevation coastal zones increase the vulnerability of Caribbean communities to coastal hazards, including tsunamis. Although tsunamis are less frequent in the Caribbean than in the Pacific or Indian Oceans, historical records indicate that both regional and transoceanic events have affected the region. The islands making up the Lesser Antilles Arc are not spared. Within this context, historical catalogues spanning approximately 500 years of European occupation report three tsunami observations in the Anguilla Bank Archipelago (including the islands of Anguilla, Saint-Martin/Sint Maarten, and Saint-Barthélemy), characterized by low-lying topography and high population densities, potentially enhancing tsunami exposure.

In the study the researchers modelled earthquake sources representative of regional faults which are trending E-W, NE-SW and NNW-SSE which structure the northern Lesser Antilles Arc. In addition, the authors also model the 1755 Lisbon transoceanic tsunami which has been reported in other islands of the arc. We then evaluate the resulting wave propagation, as well as the patterns of coastal amplitudes and current velocities around the Anguilla Bank. The results indicate that, for the set of scenarios tested and the spatial resolution of the simulation grids (~ 115 m), the Anguilla Bank generally appears moderately impacted with wave amplitudes around 1 m along its coasts, which depends on bathymetric configuration and regional wave propagation patterns. However, the limited number of scenarios considered does not cover the full range of possible tsunamigenic events, although the azimuthal coverage is highly relevant given the regional tectonic context. Alternative rupture geometries or source locations could produce higher wave amplitudes and non-seismic sources (e.g., landslides and volcanic eruptions) might also be taken into consideration in further modellings. These findings contribute to a preliminary assessment of tsunami hazard in the Anguilla Bank Archipelago and highlight the need for broader scenario exploration and multi-hazard approaches in future studies.