By COLIN M. STEWART
Computer modeling by researchers at the University of Hawaii projects that debris from Japan’s tsunami will reach the Big Island in three to five years.
The 9.0-magnitude earthquake March 11 triggered a massive wall of water that surged over coastal towns near Sendai, Japan. Homes, vehicles and even people were washed out to sea.
Rescuers worked around the clock pulling out survivors, some miles from where they’d been taken. But left behind were enormous masses of floating debris. That debris is now being carried eastward by the surface current phenomenon known as the North Pacific Subtropical Gyre, according to scientists at the University of Hawaii at Manoa International Pacific Research Center.
A project headed by the research center’s Nikolai Maximenko has spent many years tracking the current, using drifting buoys outfitted with Global Positioning System devices. Using the data from those buoys, Maximenko and his partner, Jan Hafner, have come up with a computer model that predicts the movement of floating objects caught in the gyre.
Their work has helped to explain the existence of large floating patches of garbage in the world’s oceans, including the so-called North Pacific Garbage Patch, a swirling island of plastic, chemical sludge and other debris that covers an area roughly twice the size of Texas.
According to their projections, debris from the Japan tsunami will drift eastward, and within a year bypass Hawaii to the north. The Northwestern Hawaiian Islands Marine National Monument should see pieces washing up on its shores.
Within two years, pieces of flotsam will reach the other Hawaiian Islands. But the concentrated mass of the debris will continue moving eastward, reaching the U.S. West Coast within three years, dumping debris on beaches from Alaska to British Columbia, down through California to Baja.
From three to five years after the tsunami, the mass of debris will have continued on southward and entered into the clockwise vortex of wind and current that forms the North Pacific Garbage Patch. It will continue to swirl there for years, with occasional patches breaking off and making their way to the Big Island, with some landing on beaches like South Point’s Kamilo Beach, which a BBC documentary named “the dirtiest beach in the world” because of its propensity for attracting debris from the garbage patch.
“In five years, Hawaii shores can expect to see another barrage of debris that is stronger and longer-lasting than the first one. Much of the debris leaving the North Pacific Garbage Patch ends up on Hawaii’s reefs and beaches,” reads a statement from the Pacific Research Center.
“We don’t know exactly how it will get there,” Hafner added Friday by phone from Honolulu. “It’s like making a weather prediction. You know it will rain, but not exactly when. …
“But what we know from our experience is that it’s highly probable, almost certain, that part of the Japanese tsunami debris will end up in the North Pacific Garbage Patch, where most Pacific garbage ends up.”
He added that the location of the garbage patch shifts from year to year, based on weather patterns, seasons and the effects of El Niño. But, he said, very often sections of debris “become detached and go west and hit Hawaii Island.”
What isn’t deposited on the Big Isle or the other Hawaiian Islands makes its way westward, he said, almost all the way back to Japan before moving northeastward and back into the cycle toward the U.S. West Coast.
Hafner said that he couldn’t be sure whether the amount of debris washing up on the Big Isle’s shores would be much more than what usually breaks off from the garbage patch, but he did say that the contents of the debris would be noticeably different.
“We don’t know the exact composition of debris from Japan,” he said. “On a few images we could see courtesy of the U.S. Navy (taken) during rescue missions, it appears to be mostly driftwood. …
“Normally the garbage patch is made up of trash washed down from rivers. It’s more or less what you would find in a garbage can. But this tsunami was a disaster event. The water would take everything not bolted down. Airplanes, cars, everything. So it’s not just household rubbish. You might see different types of unusual items being washed up on beaches on the Big Island. … Car parts, parts of buildings. Anything.”
As for the possibility of radiation leaked from the Fukushima Nuclear Power Plant riding the gyre to Hawaii, Hafner said he could only make an educated guess.
“If it’s liquid, it behaves differently. With the vastness of the ocean, chances are that it would be diluted,” he said. “But, if radioactivity is attached to floating debris, it’s a different story. … There is the potential.”
However, he said, he was not qualified to predict the behavior of radioactivity. “I wouldn’t want to alarm people about imminent danger,” he said. “It’s 1,000 miles from Hawaii now, and it won’t reach here for another year.”
As director of research and a cofounder of the Hawaii Wildlife Fund, Bill Gilmartin has worked since 2003 to organize cleanups of the Big Island’s shores.
At times, he said, it feels like an uphill battle, with some beaches blanketed by garbage just a week after being cleaned. But, he said, he views his mission not as keeping the beaches clean but as removing garbage from the water.
“What we’re doing is keeping it out of the ocean,” he said. “A lot of the material (on the beaches) refloats. The more we’re able to pull off the beach, the more we’re keeping from going back into the ocean. The goal is to reduce what is going into the ocean.”
Gilmartin said that while news of the Japan debris making its way to Hawaii was upsetting, chances are that his job can’t get much more difficult.
“From the 10 miles of coast from South Point back towards Hilo, we’ve collected 130 tons (of garbage) in seven or eight years,” he said. “We’re dealing with a remote coastline with dirt or lava roads. But we’ve developed a pretty good mechanism for removing the items. … It (the Japanese debris) may increase some of the volume we’ll be taking in, but I don’t think it’ll make it that much harder.”
He said his confidence springs from the fact that the Big Island community has rallied around the effort to keep its beaches clean.
“We have now well over 400 people who have helped over the years on our email list,” Gilmartin said. “We usually get anywhere from 30-100 people to show up for cleanups.”
He added that people interested in joining the list may email firstname.lastname@example.org.