Caribbean faces tsunami threat

2005-01-21 08:04

Puerto Rico - Scientists predict killer tsunamis could strike the Caribbean, which lacks an adequate warning system even though its seabed is gouged by some of the world's deepest trenches where tidal waves are generated.

The last struck the region in 1946, but that was before island populations grew massively, construction dotted shorelines and the region developed into a tourist destination which attracted 17 million visitors last year.

"The Caribbean is a very dangerous place for tsunamis," said Uri ten Brink, a US Geological Survey geologist and co-author of an article on the threat in the Journal of Geophysical Research.

The article was published two days before the Asia tsunami hit. It was triggered by a quake along the long north-south fault where the edge of the Indian plate dives below the Burma plate, known as the Sunda Trench.

The Puerto Rico trench - one of the deepest in the world at 8 207 metres - is a 900-kilometre-long underwater canyon and fault line that runs parallel to the US island territory and east of the Lesser Antilles islands.

Tensions in the Puerto Rico, Hispaniola and Cayman Trenches which ring the Caribbean, force tectonic plates to sink under one another as they collide, producing earthquakes, underwater landslides or tsunamis. The deeper the water, the quicker waves form.

Warning system needed

The last tsunami here occurred in 1946 when an 8.1-magnitude earthquake in the Hispaniola Trench triggered a tidal wave that killed an estimated 1 700 people in the Dominican Republic and Haiti, Ten Brink said.

Major earthquakes erupt about every 50 years in the Caribbean, a region where even minor natural disasters can kill thousands because of environmental degradation, shoddy construction and the large numbers of people living in coastal areas or on low-lying islands.

The Caribbean has an effective hurricane warning system and a number of tidal gauges to measure sea height. But it lacks a centralised system to alert all islands to a tsunami.

"The Caribbean needs a tsunami warning system," Ten Brink said.

The US government uses a system called Dart - Deep-ocean Assessment and Reporting of Tsunamis - with pressure recorders anchored to the sea floor detecting tsunamis as small as one centimetre.

A link transmits data to an attached buoy that relays information to alert centres via satellite.

There are only six Dart buoys in the world and they are all in the northeast Pacific Ocean, Ten Brink said. Last week, the US government announced a $37.5m plan to put 32 Dart buoys in the Pacific and Atlantic by mid-2007.

"There is a real risk from tsunamis in the Caribbean, but the risk is small when compared to other earthquake hazards over history such as buildings collapsing and fires," said Lloyd Lynch, a seismological engineer at the Seismic Research Unit in Trinidad.

"But that could change," he added. "We're more vulnerable now because of recent coastal development."

- AP