The 2011 Tohoku earthquake and tsunami shook Japan, led to a nuclear meltdown (at a plant where accidents continue to leak radioactive water into the ocean to this day), and claimed nearly 16,000 lives.
It also ripped apart seaside communities and has been scattering debris throughout the Pacific Ocean. About 5 million tons of debris was washed out into the ocean, according to the U.S. National Oceanic and Atmospheric Administration. Nearly three-quarters of it sank right near Japan, but where did the rest of it go?
University of Hawaii scientists Nikolai Maximenko and Jan Hafner have been working for several years on mapping the trail of debris. Using an ocean-drifting model developed at the university’s International Pacific Research Center, the researchers can predict where debris will wash up, based on the movements of satellite-tracked scientific buoys and wind measurements.
They’ve created this eerily beautiful animation of how winds will affect the rate that debris moves:
These colors don’t actually represent bits of debris -- they’re a prediction of how different kinds of wreckage will move across the Pacific based on what’s called “windage.” The reddest data points represent bits of debris that float mostly above the surface of the water, like foam and plastics. These kinds of objects will move quicker across the Pacific – they’re helped along more by winds than objects that float half under the surface or that don’t float at all.
Thanks in part to their buoyancy, some of the first pieces of wreckage started washing up on North American shores only a little more than a year after the tsunami, much faster than initially expected. In April 2012, a soccer ball belonging to a Japanese teenager and a volleyball were discovered by a technician working on Middleton Island in the Gulf of Alaska; two months later, a 66-foot-long, 7-foot- tall boat dock from the northern Japanese city of Misawa washed up on Agate Beach in Oregon. NOAA had initially thought that debris wouldn’t start showing up on North American coasts until March 2013.
Last year, there were some media rumors swirling that a massive island of Japanese debris – laden with foreign animals and radioactive material – heading for North America. But that’s simply not the case, according to NOAA.
“At this point, nearly three years after the earthquake and tsunami struck Japan, whatever debris remains floating is very spread out,” NOAA said in a statement last November. “It is spread out so much that you could fly a plane over the Pacific Ocean and not see any debris since it is spread over a huge area, and most of the debris is small, hard-to-see objects.”
Ultimately, any debris that doesn’t sink or wash up on Hawaiian or North American shores could circulate back into the Pacific. Their final destination, however, hinges on the whims of wind and water.
This month, Maximenko and Hafner said that their work on ocean currents has had an unexpected outcome: It validates the seemingly improbable story of a Mexican fisherman’s 13-month odyssey as a castaway drifting through the Pacific Ocean. Jose Salvador Alvarenga said he survived in a small boat for more than a year by eating fish, turtles and birds, and drinking rainwater and turtle blood. Hafner and Maximenko happened to have placed 16 tracers in the water not too far from where Alvarenga said he drifted out, at the same time his boat was borne off course.
By January 2014, several of their tracers had drifted near Ebon Atoll in the Marshall Islands, where Alvarenga was found on Jan. 30.
His claim, therefore, “is consistent with the prevailing pattern of wind and ocean currents during his ordeal,” IPRC said in a statement.
Studying the movements of Japanese tsunami debris isn't the first time scientists have learned from stuff inadvertantly dumped in the ocean. In 1992, tens of thousands of plastic bath toys -- including iconic rubber ducks -- spilled into the Pacific from a cargo ship. Some, like the tsunami debris, headed for Hawaii; others went through the Bering Strait, got frozen in sea ice, and eventually came out on the other side of the Arctic Sea to navigate the Atlantic Ocean. Oceanographers and other scientists were keen to discover where the toys turned up, and even offered bounties to the public for turning in found ducks.
"Many people don't realize that the oceans move, that what happens here depends on what happened there," Southampton University oceanographer Peter Killworth told the Christian Science Monitor. "The ducks are a good lesson in how the environment works in a global way."
Roxanne has liked science ever since she started watching "Bill Nye the Science Guy" on Saturday mornings over a bowl of sucrotic O's. She especially likes writing about...