Barbados

Barbados is geologically distinct from most of its Lesser Antilles neighbours, sitting not on the active volcanic arc but on an accretionary prism — a wedge of sediment scraped off the North American Plate as it descends beneath the Caribbean Plate at the Lesser Antilles [[subduction-zone]]. This makes Barbados the easternmost land in the Caribbean and places it directly in the path of convergence between the two plates. The island experiences regular earthquakes, most generated by the [[subduction-zone]] interface to its west or from intraplate faults within the accretionary wedge itself. The convergence rate between the North American and Caribbean plates here is approximately 2 centimetres per year, producing a regular background of small-to-moderate seismicity. The most severe threat comes from the potential for a great subduction earthquake on the Lesser Antilles arc and an associated [[tsunami]] that could strike Barbados's east coast with limited warning. The island's relatively low elevation across most of its area would provide little protection against a significant wave.

Historical records document significant earthquakes affecting Barbados over the colonial period. The 1766 earthquake caused damage to buildings in Bridgetown. The 1843 Guadeloupe earthquake (estimated magnitude 8.0) was strongly felt across Barbados and caused widespread damage and deaths throughout the Lesser Antilles. The 1953 Barbados earthquake (magnitude 5.8) caused minor structural damage. The island felt shaking from the 2007 Martinique earthquake (magnitude 7.4), which was one of the largest instrumented events in the Lesser Antilles in recent decades, causing some structural damage in Barbados. Regional seismic events from the Caribbean plate boundary to the northwest — including events on the El Pilar Fault system off Venezuela — have also been felt. The proximity to the active subduction zone means that [[magnitude]] 6 or greater events within a few hundred kilometres can be expected several times per decade.

The geology of Barbados reflects its unique position as an uplifted accretionary prism. As the North American oceanic plate descends beneath the Caribbean Plate at the Lesser Antilles trench, sediments from the seafloor are scraped off and compressed into a growing wedge of deformed material. Barbados has been progressively uplifted by the thickening prism beneath it, exposing coral reef terraces at multiple elevations that record the island's gradual emergence over the past million years. These terraces provide one of the world's best natural records of sea-level change during ice ages. The rock of the island is predominantly coral limestone overlying deeper accretionary prism material; this porous carbonate rock provides moderate amplification of [[seismic-wave]]s but is not as susceptible to [[liquefaction]] as saturated alluvial deposits. The University of the West Indies Seismic Research Centre in Trinidad monitors regional seismicity including events affecting Barbados.