Small Islands Amplify Tsunami Flooding

Small offshore islands help protect beaches from storm waves, but they're no match for tsunamis. It turns out that small islands boost the power of big tsunami waves, rather than absorbing their impact, a new study shows. In a computer model, a small island amplified tsunami flooding directly behind it by up to 70 percent.

"Our study shows that some areas that were supposed to be at low risk are at higher risk than anticipated," said study co-author Frederic Dias, an ocean wave expert at University College Dublin in Ireland. The findings were published today (Nov. 5) in the journal Proceedings of the Royal Society A.

Tsunami waves in the ocean are generated by the sudden motion of the seafloor or by underwater landslides. The rapid movement is like a giant paddle stroke that creates a series of huge ripples that transform into terrifying waves closer to shore. The length between the top (or crest) of each wave can be as much as 100 miles (160 kilometers).

http://www.livescience.com/48638-offshore-islands-boost-tsunami-flooding.html