Living & Healthy Reefs Provide Better Tsunami Protection Than Diseased, Dead Formations - AFP

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Healthy coral reefs provide their adjacent coasts with substantially more protection from destructive tsunami waves than do unhealthy or dead reefs, a Princeton University study suggests.

Initially spurred by the tsunami that devastated the coastlines of the Indian Ocean two years ago, a team of scientists developed the first-ever computer model of a tsunami strike against a reef-bounded shoreline, using a volcanic island as an example. The model demonstrates that healthy reefs offer the coast at least twice as much protection as dead reefs. The finding provides the first quantitative confirmation of a widely held theory regarding the value of living coral reefs as a defense against tsunami waves, which are often generated by powerful undersea earthquakes.

Princeton professor Michael Oppenheimer said his team's work will give scientists the ability to quantify how much any given reef will benefit its particular stretch of coast. "Healthy reefs have rougher surfaces, which provide friction that slows the waves substantially in comparison with smoother, unhealthy ones," said Oppenheimer, the Albert G. Milbank Professor of Geosciences and International Affairs. "Scientists had never before studied this effect by the numbers, nor had they ever analyzed it over a wide variety of coastal shapes. This study provides yet another motivating factor for protecting the planet's coral reefs from degradation."

The team's findings appear in the Dec. 14 edition of the journal, Geophysical Review Letters. In addition to Oppenheimer, other team members include Robert Hallberg, who is head of the Oceans and Climate Group at the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Lab, and Catherine Kunkel, who is the paper's lead author. Kunkel spearheaded the work during her senior undergraduate year at Princeton, from which she graduated with a physics degree in June.

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