Some 3,300 years ago a tsunami must have hit the the island of Bonaire in the Caribbean, though no historical records of tsunamis exist.
Sediments don't lie and the sediments studied by scientists writing in Naturwissenschaften – The Science of Nature showed that this tsunami entirely changed the coastal ecosystem and sedimentation patterns in the area.
The Caribbean is no stranger to coastal hazards, including tropical cyclones, earthquakes, volcanoes, and tsunamis, but historical records for the island of Bonaire only go back 500 years. It has not experienced a tsunami during that time but overwash deposits from a coastal lagoon provide evidence for a real doozy of a tsunami in prehistory.
Dr. Max Engel and colleagues from the University of Köln investigated sediment cores from Washington-Slagbaai National Park. They looked specifically at grain size distribution, carbonate content, organic matter, magnetic susceptibility and fauna. Their analyses showed that the sediments had criteria typically linked with tsunami deposits, consistent with a tsunami with a maximum age of 3,300 years.
The authors conclude: "This single catastrophic event is of long-term ecological significance. Formation of a barrier of coral rubble was triggered by the tsunami separating a former inland bay from the open sea and turning it into a highly saline lagoon which persists until today. Further studies of the geology of tsunamis, using well-dated deposits, are required over the entire Caribbean to reconstruct reliable patterns of magnitude, frequency and spatial occurrence of tsunami events and their environmental impact."