Giant Underwater Waves Churn Off Hawaii Shores

Waves the height of skyscrapers are churning the waters of the Pacific just off Hawaii, scientists reported Wednesday, but there’s no chance of tsunami, and boaters won’t even notice. The waves are underwater.

A three-year project has been charting waves and subsurface tides up to 1,000 feet high that researchers say offer new information about the often mysterious mixing of ocean waters that warms lower depths and allows sea life to prosper.

“Imagine such a wave on the surface. It would be quite a frightening sight,” said Daniel Rudnick of the Scripps Institution of Oceanography at UC San Diego.

Scientists now have concrete evidence that the 1,600-mile mostly underwater volcanic ridge that forms the Hawaiian and Northern Hawaiian Islands also forms an underwater barrier to tides that spawn the giant water movements, said researcher Robert Pinkel, who is also with the Scripps Institution.

Rudnick, Pinkel and other scientists reported the latest studies of the Pacific at the annual Ocean Sciences Meeting here.

Waves break in the hidden depths off Oahu and Kauai just as the surf does on Hawaii’s beaches, Pinkel said.

“Their signature on the surface is very slight,” he said, describing the underwater turbulence as a life-sustaining phenomenon.

Scientists describe the mixing of the oceans as essential to maintaining temperatures and dispersing nutrients for sea life. But less than 10% of the mixing is completely understood, and extensive research remains to be done, Pinkel said.

Where the sea floor is roughest, the mixing rates are 1,000 times more intense than places without such topography, according to Tom Sanford and Eric Kunze of Washington’s Applied Physics Laboratory.