The Great Lisbon Earthquake

St. Augustine, Trinidad and Tobago – A tsunami is an ocean wave or series of waves caused by a large-scale disturbance of the ocean floor or surface that abruptly displaces a large mass of water.

Tsunamis may be caused by earthquakes, volcanic events, landslides into the sea or impact of stellar objects such as asteroids, comets and meteorites. {{more}}

While it is possible for the region to be hit by a tsunami such as the one recently experienced in Asia, scientists currently believe that there is a very low probability of this phenomenon occurring in the Caribbean.

In the past 500 years there have been at least 10 earthquake-generated tsunamis in the entire Caribbean which have been reported and verified. Four of these have led to deaths. In total about 350 people in the Caribbean have been killed by these events. These tsunamis occurred as a result of earthquakes in:

• May 1842, Haiti – An intense local tsunami was believed to have killed up to 200 people in the town of Port-de-Paix. This figure is highly uncertain since total casualties caused by the earthquake were more than 7,000.

• November 1867, Virgin Islands – Death toll about 20, all in the Virgin Islands.

• October 1918, Puerto Rico – Death toll about 29 in Puerto Rico.

• August 1946, Dominican Republic – An intense local tsunami that mainly affected the town of Matanzas where up to 100 people were killed.

Additional earthquake-generated tsunamis of note also occurred in 1843 affecting Guadeloupe and Antigua and in 1690 in St. Kitts/Nevis. The number of casualties related to these tsunamis, if any, is uncertain. In July 2003, a major dome collapse from the Soufriere Hills Volcano in Montserrat caused a tsunami that was experienced in Guadeloupe at about 1m high and in some parts of Montserrat at 4m in amplitude.

Potentially, there are two groups of earthquakes that may generate tsunamis in the Caribbean. These are: (1) Earthquakes occurring within the region which may generate local tsunamis (by local we mean that only nearby islands are affected). In the past 500 years there have been approximately 50 potentially tsunamigenic local earthquakes but only 10-20 per cent of these earthquakes actually generated tsunamis that caused significant inundation. (2) Distant earthquakes occurring outside of the region may generate tele-tsunamis.

In November 1755, a major earthquake in the Azores fracture zone near Portugal resulted in a tele-tsunami which crossed the Atlantic and was noticed throughout the eastern Caribbean from Barbados to Antigua and as far west as Cuba. This earthquake is commonly referred to as the Great Lisbon Earthquake. The amplitude of the tsunami in all islands was about 2-3 metres and waves continued to arrive for many hours. No damage or casualties were reported.