Big debris from Japan could arrive in a year

A University of Hawaii scientist said he expects heavy debris from the 2011 Japa­nese tsunami to reach small atolls in the Northwestern Hawaiian Islands within a few months and the main Hawaiian Islands in about a year.

Nikolai Maximenko, a senior researcher with the International Pacific Research Center and an expert in the movement of currents, said Tuesday the debris will eventually reach mainly windward shores, including Kahuku Beach on Oahu and Kamilo Beach on the southeastern part of Hawaii island.

Maximenko said an earlier prediction had the debris reaching Midway Atoll by February, but a late winter has pushed back the date of its arrival by anywhere from a few weeks to a few months.

He said because of variables in the ocean including winds, some debris that is light could reach Hawaii before the end of the year.

Lumber, boats and other debris ripped from Japa­nese coastal towns by the tsunami on March 11 have spread across some 3,000 miles of the North Pacific, where they could wash ashore on remote islands north of Hawaii this winter, the National Oceanic and Atmospheric Administration said in a separate news release Tuesday.

NOAA’s tsunami marine debris coordinator, Ruth Yender, told an online news conference Tuesday that agency workers were boarding Coast Guard flights that patrol the archipelago. NOAA also asked scientists stationed at Midway and other atolls to look for the debris.

Debris initially collected in a thick mass in the ocean after waves dragged homes, boats, cars and other parts of daily life from coastal towns out to sea. Most likely sank not far from Japan’s eastern coast.

In September a Russian training ship spotted a refrigerator, a television set and other appliances west of Hawaii. By now the debris has likely spread so far apart that only one object can be seen at a time, Maximenko said.

Some 1 million to 2 million tons of debris remain in the ocean, but only 1 percent to 5 percent of that could reach Hawaii, Alaska, Oregon, Washington state and British Columbia, Maximenko said. The tsunami generated 20 million to 25 million tons of debris, including debris left on land.

Yender said that so far, no debris confirmed to be from the tsunami has landed on American shores, including large buoys suspected to be from Japa­nese oyster farms found in Alaska last year. The buoys would have had to travel faster than the currents to get to Alaska at that time if they were set loose by the March 11 tsunami.

Similar buoys had washed ashore in Alaska and the West Coast before the tsunami, she said.

Nicholas Mallos, a conservation biologist and marine debris specialist for the Ocean Conservancy, said many of the objects in the debris were expected to be from Japan’s fishing industry. That could pose a risk for wildlife, such as endangered Hawaiian monk seals, if fishing gear washes up on coral reefs or beaches.

"The major question is how much of that material has sank since last year, and how much of that remains afloat or still in the water column," Mallos said.

Maximenko said the dispersion of the debris makes it more difficult to track but no less hazardous.

"In many cases it’s not density that matters, it’s total amount," he said. "For example, if there’s a current flowing around Midway island, that island would collect debris like a trawl moving across the ocean. It will collect all the debris on its way."

Ultimately, Maximenko said, tsunami debris will join garbage floating in a gyre north of Hawaii produced by swirling Pacific currents. Much of that trash in a wide area known as the Great Pacific Garbage Patch is bits of plastic, which slowly breaks down into smaller pieces but doesn’t completely disappear.

It was unclear whether large items like refrigerators will make it across the ocean because there has been little precedent for such an event.

Maximenko said the tsunami-swept debris presented a "unique" problem and an opportunity to concentrate resources to intercept and pick it up.

But he said most agencies are designed to respond to the loss of property and human life.

He said researchers were continuing to track and analyze the debris.