Tsunami to Hit Caribbean When Million-Ton Rock Falls?

Kate Ravilious
for National Geographic News
April 27, 2009

Editor's note: This story originally described the projected tsunami as being ten stories tall. The text has been corrected to say "ten-foot-tall (three-meter-tall) tsunami" (May 6, 2009).

With only a few minutes' warning, a ten-foot-tall (three-meter-tall) tsunami will shatter the usual peace of the Caribbean resort islands of Guadeloupe, a new study says (tsunami facts).

The tsunami is expected to be generated when a major landslide, on the island of Dominica—about 30 miles (50 kilometers away)—plunges up to a million tons of rock into the sea (Dominica and Guadeloupe map).

"It is not a case of if the landslide and tsunami will happen, but when," said Richard Teeuw, from the University of Portsmouth, U.K., who led the team of geologists that made the discovery.

"Most likely it will be triggered by a major earthquake," Teeuw added. "It could happen in a hundred years, or it could happen next week."

As many as 30,000 people could be at risk, the researchers say.

Seismology—Powered by Google Earth?

Using satellite images from the Google Earth software, Teeuw and his team surveyed Dominica, gaining a bird's-eye view of rock outcrops normally obscured by vegetation.

They noticed that the north coast of the island is unusually straight, indicating active earthquake faults.

Further investigations on the ground revealed large tension cracks along the flank of a volcano, Morne aux Diables (Devils' Peak)—convincing the team of the landslide threat (volcano facts).

Defenseless?

Speaking at a press conference Friday, Dominica's disaster-preparedness minister sought to quell panic over the findings.

"There is no scientific indication that such an event is imminent and therfore [sic] we should begin to take measures immediately," Charles Savarin said, according to Dominica News Online.

No matter when the landslide strikes, Guadeloupe, a French territory, would be largely at the mercy of any potential tsunami.

Currently there are no tsunami early-warning systems in the Caribbean—and very little to brunt the impact.

"Prevention is the most important thing for Guadaloupe," said study co-author Carmen Solana, also from the University of Portsmouth.

"Perhaps some artificial reefs, or even a small, half-metre [foot-and-a-half] promenade wall can reduce the energy of the tsunami waves."

Findings published April 21 in the newsletter of the American Geophysical Union.

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