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The Japan Tsunami Marine Debris Summary

March 20, 2013
Japanese dock

A dock that washed up at Olympic National Park, WA

Two years have passed since a massive earthquake and tsunami struck northeastern Japan, killing thousands and devastating coastal communities. The Government of Japan estimated that 1.5 million tons of floating debris dispersed widely over the North Pacific Ocean, carried by ocean currents and prevailing winds. Starting in the winter of 2011-2012, debris reached Alaska and West Coast states, and later Hawai’i. Federal and state agencies, tribes, NGOs, academia, and industry have been working together to address this unprecedented challenge.

Efforts to assess the problem began immediately after the event. A month after the tsunami, debris was so dispersed it could no longer be detected by satellite. Computer models estimated the movement of tsunami debris over time. A NOAA model showed that high floating debris, such as floats and foamed plastic, arrived on the West Coast, Alaska, and
Hawai’i over the winter of 2011-2012 in an intermittent and widely scattered manner. Long-term forecast modeling, done by NOAA and Japan, suggests decreasing amounts of debris arriving over the next year.

To date, over 1,500 potential marine debris items have been reported through . Japanese authorities have confirmed 21 reports as Japan tsunami marine debris (JTMD). Two floating docks, several small boats, storage boxes, soccer balls, a motorcycle, buoys, and a decorated float are among confirmed JTMD. Unconfirmed items, lacking markings to directly tie them to the tsunami event, included small boats spotted in the Pacific Ocean or found on-shore, packaging material such as foam pieces, pallets, floats, and a variety of small debris. For more information, go to:

Most of the debris from the tsunami could not be readily distinguished from normal marine debris and in many cases, was handled as part of existing efforts. States provided disposal bins, cleanup supplies, and contracted cleanup crews. Some debris items like small boats, have required additional efforts to remove. Two floating docks—one that beached near Newport, Oregon in June 2012 and the other in Olympic National Park in Washington in December 2012 (above)— have presented the largest individual challenge to remove and have posed significant risk of aquatic invasive species. State-specific response plans and table top exercises have been valuable tools to address these challenges.

As we enter the third year since the tsunami event, agencies have greater experience, expertise, and protocols to address any additional JTMD reaching North America and Hawaii. Modeling suggests that with the passage of time, less and less tsunami debris will wash up on our shores, and the tsunami debris blends into the existing debris that already plagues our shores.

From the NPS Pacific Oceans Newsletter – March 2013

One Comment leave one →
  1. Wayne permalink
    March 29, 2013 1:12 am

    Thank you for the update, glad that efforts are being made to collect this marine pollution and monitor where it is and what invasive species might travel with it. However just to be clear there is no such thing as “normal” marine debris, it is all pollution in our seas that is sourced from human activities.

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