Caribbean vulnerable to Tsunamis!

[msbee]

Caribbean Vulnerable to Killer Tsunamis

1 hour, 5 minutes ago

By FRANK GRIFFITHS, Associated Press Writer

SAN JUAN, Puerto Rico - Scientists predict killer tsunamis could strike the Caribbean, which lacks a warning system even though its seabed is gouged by some of the world's deepest trenches, where the giant waves can be generated by tectonic activity, and its low-lying islands are heavily populated along their coastlines.


The last tsunami struck the Caribbean in 1946, before island populations skyrocketed, major construction dotted shorelines and the region developed into a prized tourist destination attracting 17 million visitors last year.

"The Caribbean is a very dangerous place for tsunamis," said Uri ten Brink, a U.S. Geological Survey (news - web sites) geologist in Woods Hole, Mass., and co-author of an article on the threat in the Journal of Geophysical Research. "The Caribbean needs a tsunami warning system."

The article was published two days before a Dec. 26 earthquake under the Indian Ocean generated a tsunami that killed at least 157,000 people in 11 nations. The quake occurred along the long north-south fault in the Earth's crust where the edge of the Indian tectonic plate dives below the Burma plate, forming the Sunda Trench.

That trench is about 25,000 feet deep.

The Puerto Rico Trench — one of the deepest in the world at 27,355 feet — is a 560-mile-long underwater canyon and fault line running parallel to this U.S. island territory and east of the Lesser Antilles islands.

Seismic tensions in the Puerto Rico, Hispaniola and Cayman trenches ringing the Caribbean force tectonic plates to sink under one another as they collide, producing earthquakes, underwater landslides or tsunamis.

A tsunami is a series of waves formed by a disturbance in sea level over a short period of time, such as an earthquake, underwater volcanic eruption or coastal landslide.

In the deep and open ocean, the waves can travel at up to 600 mph but be no more than 2 feet high, making them imperceptible to the human eye.

The last fatal tsunami here occurred in 1946 when an 8.1-magnitude earthquake in the Hispaniola Trench triggered waves 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 many people who live 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 centralized system to alert all islands to a tsunami.

The United States uses a system called Deep-ocean Assessment and Reporting of Tsunamis, or DART, with pressure recorders anchored to the sea floor detecting tsunamis of less than a half-inch in height. A link transmits data to a buoy that relays information to alert centers via satellite.

There are only six DART buoys in the world and they are all in the northeast Pacific Ocean, Brink said. Last week, the U.S. government announced a $37.5 million plan to put 32 DART buoys in the Pacific and Atlantic oceans by mid-2007.

From 1900 to 2001, there were 796 tsunamis observed or recorded in the Pacific, according to the Pacific Tsunami Warning Center.

"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. We're more vulnerable now because of recent coastal development."

One reason the Asian tsunami proved so deadly was that a 750-mile plate lifted as the pressure built, producing a magnitude 9.0 quake. Because the Caribbean trenches are shorter, they would be unlikely to produce such a strong eruption, ten Brink said.

Still, because of development and population growth, an 8.1-magnitude earthquake followed by a tsunami could be much deadlier than the 1946 wave, he said.

Members of the Caribbean Disaster Emergency Response Agency will meet in May with scientists and disaster coordinators to discuss the need for an early warning system, said Terry Ally, a spokesman for the Barbados-based agency.

"It's a matter of time before a tsunami happens in the Caribbean," said Christa von Hillebrandt, director of the Puerto Rico Seismic Network. "All the ingredients are there."

[cycloneye]

Yes they haved been talking here about that since the December 26 Tsunami in SE Asia.We haved experienced those in past centurys the last Tsunami was at 1918 aftera 7.3 quake at Western Puerto Rico.And the population is growing in Puerto Rico in a rapid rate and the constructions of condos are many near the coast.

[Patrick99]

Tsunamis in the Caribbean would likely have little or no effect on Florida, right?

I'm not sure any measurable tsunami could ever hit South Florida. *Maybe* Jupiter Inlet and points north. It would seem to me that any wave would break and dissipate on the Great Bahama Bank. Of course, from the south, there's Cuba and Hispaniola right in the way.

[jinftl]

I was thinking the same thing....wouldn't the Bahamas bear the brunt of an Atlantic tsunami in that region....breaking it up before it reached South Florida?

[cyclonaut]

if it a big one I doubt it!

But then again Im not a tsunami expert.

[tronbunny]

I was thinking the same thing....wouldn't the Bahamas bear the brunt of an Atlantic tsunami in that region....breaking it up before it reached South Florida?

Ahhh, not so.
I'll do a thread search.
There was a discussion of the possibility of a canary island landslide triggered tsunami that would devastate the entire CONUS east coast.

Sorry, couldn't find the storm2K post.. but

http://www.etherzone.com/2004/bren122904.shtml

"A massive chunk of La Palma, the most volcanically active island in the Canaries archipelago, is unstable, British geologist Simon Day warned yesterday. Dr. Day, of the Benfield Grieg Hazard Research Centre at University College London, said the 500 billion ton rock could collapse the next time the volcano, Cumbre Vieja, erupts.

That would send a dome-shaped wall of water up to 100m tall - 10 times as high as the tsunamis that hit south Asia - racing across the Atlantic at 800km/h. Waves would hit the west coast of Africa and the south coast of England within a few hours, he said. Eight hours after the collapse, the US east coast and the Caribbean would bear the brunt. Cities from Miami to New York would be swamped by waves up to 50m high, capable of surging 20km inland, according to Dr. Day's research."

[cyclonaut]

Here some good info on this subject...

http://www.es.ucsc.edu/~ward/papers/La_Palma_grl.pdf#search='tsunami%20La%20palma%20Cumbre%20Vieja'

http://www.cdnn.info/article/tsunami/tsunami.html

[Persepone]

Not having a disaster warning system in general seems to have been as much of a problem in SE Asia as not having a Tsunami warning system.

How do they warn of other hazards in Puerto Rico now? Radio/TV/NOAA Radio/Sirens on Beaches? Is there a good warning infrastructure in place? I think if there is an earthquake of any magnitude reported it should be possible to issue some warnings on existing warning networks, etc. to tell people to get off the beaches and to higher ground, etc. At least it might stop people from standing there and watching the water recede on the beaches and the fish flop around on the ocean floor before the wave comes crashing in...

Then it's a question of having the emergency management people figure out where the safest places to go would be and publicizing this information and perhaps putting up signs for best evacuation routes, etc. Especially if those evacuation routes are the same as those for hurricanes and other more common (locally) disasters.

The technology for automated warning systems is a wonderful thing, but plain old intelligent planning and good communications, up to date phone numbers, etc. and automated "call trees" (telephone equipment that automatically dials hundreds of pre-programmed numbers quickly/simultaneously with a recorded message) and some public awareness should be able to save a lot of lives in the event of a Tsunami.

My personal opinion is that the biggest problem is that "tourists" in any area are unaware of local hazards, best routes to safety, etc. An often they do not listen to local radio stations, etc. I've traveled in lots of places where I was totally unaware of a potential hazard until I read a sign telling me about it. The awareness provides a lot of protection in and of itself. It is sort of like paying attention to the location of exits in a public place, in a hotel, etc.

While waiting for the DART warning system, it seems as though there are a lot of intelligent people who could figure out an interin warning system that would be better than no warning system. Also, some education in the schools, etc. would help to make children aware of the danger. There was some news story about a British child who had studied Tsunamis who saw what was happening on the beach and warned people around her and she--and about 100 other people--managed to make it to safety in time!

[Patrick99]

Here some good info on this subject...

http://www.es.ucsc.edu/~ward/papers/La_Palma_grl.pdf#search='tsunami%20La%20palma%20Cumbre%20Vieja'

http://www.cdnn.info/article/tsunami/tsunami.html

According to the diagrams in the first link, Miami-Dade and Broward counties *would* be spared, as I expected. It wouldn't make any sense for a wave to just run up over the Bahama Bank relatively unaffected and smash into Miami Beach. It's an awfully big sandbar for it not to have a major impact on a tsunami.