Ocean Recovery Alliance

Pacific Ocean Survey Northwest of Midway Atoll in Expectation of Tsunami Debris from Japan

By Ocean Recovery Alliance

- Published on January 26, 2012 by

 

ora   iprc     university of hawaii    scripps

Pacific Ocean Survey Northwest of Midway Atoll in Expectation of Tsunami Debris from Japan 

HONOLULU, HAWAII - January 20, 2012 - The March 11, 2011 earthquake northeast of Japan, and the impact of subsequent tsunami wave on the Tohoku coastline, produced as much as 25 million tons of debris. A large amount of the debris was then released into the ocean. Under the influence of winds and currents, floating debris is dispersing over a large area and drifting eastward; it is predicted to reach Hawaii and the West Coast of the United States within the coming two years. The composition of the debris and the amount of it remaining on the sea surface is largely unknown. However, one thing is certain: it is hazardous to marine vessel navigation, marine life and, when washed ashore, to coastlines. 

Shortly after the tsunami, a team of scientists and conservationists from the University of Hawaii at Manoa (Drs. Nikolai Maximenko and Jan Hafner) and Hilo (Dr. Henry Carson), the Scripps Institution of Oceanography (Dr. Luca Centurioni) and the Ocean Recovery Alliance (Mr. Douglas Woodring) created a plan to survey the tsunami debris field and to mark it with satellite-tracked drifting buoys. The drifter array would then be used to monitor the movement of the debris and to send warnings if the debris approaches critical areas.  Numerical models, based on trajectories of historical drifters, predicted that Midway Atoll and the rest of Papahanaumokuakea Marine National Monument are likely to be impacted by tsunami debris as early as the winter of 2012. This prediction was supported in September 2011 by the Russian Sail Training Ship "Pallada," which reported the edge of the debris field to be 250 miles from Midway and picked up a 20 foot boat that was lost during the tsunami, about 350 miles northwest of the atoll.

In December 2011, in the face of the growing strength of winter storms, the team led a successful expedition that surveyed probable pathways of the leading edge of tsunami debris near the Northwest Hawaiian Islands and deployed 11 drifting buoys designed to simulate the motion of different types of debris. The data from these drifters, used in conjunction with computer models, will give scientists and operational agencies greater awareness of the status of the expected debris flow movements.

map of debris flow

The above map shows the path of the expedition (black line), the sightings of debris (red), and the trajectories of the deployed drifting buoys, superimposed on streamlines of surface currents, assessed by the SCUD model.

One of the most important results of the expedition was the discovery that, contrary to predictions, tsunami debris was not recently advancing towards Midway Atoll.   Instead, this expected movement had been stopped by a front and its associated northeastward jet stream, located 300-400 miles northwest of the atoll.  This front has effectively separated the area which contains the tsunami debris from the islands.  The dominant water flow around all the Hawaiian Islands is currently from the southeast.  This flow prevents the tsunami debris from approaching the islands but carries a lot of “ordinary” debris (mainly old plastic) from the North Pacific Gyre where convergent ocean currents collect everything that floats at the sea surface.  Samples of this ordinary debris (not from the tsunami) were collected and photographed for documentation during the expedition.  

The 11 satellite-tracked drifters were deployed along a line in order to mark the area of expected leading edge of the tsunami debris field facing Midway Islands.  Scientists at Scripps Institution of Oceanography will now be able to remotely monitor the movement of this part of the debris field.   In addition, 400 numbered wooden blocks were deployed along the route, either in the vicinity of floating objects.  If these blocks are recovered by boaters, fishermen and beachgoers who subsequently notify scientists via the contact information on the blocks, they can help improve the understanding of the motion of debris and currents in this part of the ocean. 

The expedition exchanged observations with the volunteer group on Kure Atoll and the management of Midway Islands. Both groups reported an abundance of old debris arriving on southern beaches of the atolls, consistent with the conclusions of the expeditions and of the diagnostic models created at the International Pacific Research Center. Systematic examination of samples (including water samples) with a Geiger counter has not revealed any outstanding radiation.

Information on the tsunami debris tracking project can be found at:  http://www.oceanrecov.org/tsunami-debris/about.html

 

About the International Pacific Research Center

The International Pacific Research Center (IPRC) at the School of Ocean and Earth Science and Technology (SOEST), University of Hawaii at Manoa, is a climate research center founded to gain greater understanding of the climate system.  The center studies the nature and causes of climate variation in the Asia-Pacific region, and how global climate changes may affect the region.  Established under the "U.S.-Japan Common Agenda for Cooperation in Global Perspective" in October 1997, the IPRC is a collaborative effort between agencies in Japan and the United States. Research on marine debris in general and tsunami debris in particular is summarized at http://iprc.soest.hawaii.edu/news/marine_and_tsunami_debris/debris_news.php

About Scripps Institution of Oceanography

Scripps Institution of Oceanography, at the University of California, San Diego, is one of the oldest, largest and most advanced centers for global marine research and education in the world. The National Research Council has ranked Scripps first in faculty quality among oceanography programs nationwide.  Now in its second century of discovery, the scientific scope of the institution has grown to include biological, physical, chemical, geological, geophysical and atmospheric studies of the earth as a system. Hundreds of research programs covering a wide range of scientific areas are under way today in 65 countries. The institution has a staff of about 1,300, and annual expenditures of approximately $155 million from federal, state and private sources. Scripps operates one of the largest U.S. academic fleets with four oceanographic research ships and one research platform for worldwide exploration.  www.scripps.ucsd.edu 

About the Ocean Recovery Alliance

The Ocean Recovery Alliance, a registered non-profit organization in Hong Kong and California, was established in 2010 in order to bring new technologies, innovations, creativity and collaborations to solve issues that face the health of the ocean today.  One of the main focuses is on plastic pollution, and the group has made two commitments related to the reduction and prevention of global plastic pollution at the Clinton Global Initiative.  The Tsunami Debris Tracking Project will help increase the awareness of plastic and debris in our ocean. www.oceanrecov.org

 

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