U.S. Extended Continental Shelf Project Holds Workshop in Woods Hole, Massachusetts
The U.S. Extended Continental Shelf (ECS) Project held its 2012 Technical Workshop at the U.S. Geological Survey (USGS) Woods Hole Coastal and Marine Science Center in Woods Hole, Massachusetts, during the week of April 16, 2012. The workshop followed 18 months of gathering data and background from seven offshore regions of the United States where an extended continental shelf might exist.
Where a nation can demonstrate that it has extended continental shelf—seafloor beyond 200 nautical miles from shore that meets criteria set forth in Article 76 of the United Nations Convention on the Law of the Sea (http://www.un.org/Depts/los/)—it can exercise certain sovereign rights over seabed and sub-seabed resources there. Preliminary studies have indicated that the U.S. extended continental shelf likely totals at least 1 million square kilometers—an area about twice the size of California or nearly half the Louisiana Purchase. Data collection and analysis will help the ECS Project come to a more definitive conclusion as to the extent of U.S. extended continental shelf; progress in that direction was the aim of the April workshop.
The workshop’s 22 attendees came from the three agencies that lead the U.S. ECS Project: the Department of State, the National Oceanic and Atmospheric Administration (NOAA), and the Department of the Interior. These participants—including members of the ECS Executive Committee, regional team leads, and a subset of team members—represented a broad range of expertise in geology, geophysics, hydrography, data management, and law. The workshop gave them a unique opportunity to discuss multiple facets of integrating the Earth sciences with law, coming to a greater understanding about associated ambiguities and differing perspectives. Overall, the workshop was intense, focused, and productive and was deemed a success by all who participated.
The workshop opened with a full day of presentations on seven regions of possible U.S. extended continental shelf: Gulf of Mexico, Non-Arctic Alaska (the Bering Sea, the Gulf of Alaska, and the Aleutian Islands), Atlantic, Arctic, Pacific West Coast (California and Oregon), Western Pacific, and Central Pacific. The leads for each Integrated Regional Team (IRT) discussed preliminary findings for their regions based on analysis of currently available data. Participants aimed to understand how the criteria were applied in the different regions, eliminate scenarios that had been ruled out by analyzing existing and new data, and strive to develop an approach consistent with Article 76.
Ginger Barth (USGS), IRT lead for Non-Arctic Alaska, presented her group’s findings and some preliminary results from her 2011 seismic cruise across the Surveyor and Baranof submarine-fan systems (see “Three-Week Expedition Images Sediments Beneath the Gulf of Alaska,” Sound Waves, August 2011).
Western Pacific IRT lead Dan Scheirer (USGS) led discussions about the areas both east and west of the Mariana Island Arc (Guam, Saipan, and Farallon de Pajaros). The NOAA/University of New Hampshire Joint Hydrographic Center (http://ccom.unh.edu/) has conducted three multibeam seafloor-mapping cruises in this region. The complex tectonic history and seafloor topography in these areas led to some challenging discussions about identifying the “base of slope”—a critical parameter for applying the formulas in Article 76.
Matt Arsenault (USGS) presented results from two extended-continental-shelf regions in the Gulf of Mexico that lie beyond the 200-nautical-mile limits of the United States, Mexico, and Cuba: the so-called Western and Eastern Polygons. Abundant data from academic studies and hydrocarbon exploration are available for these regions, and the Western Polygon has been chosen for a pilot submission exercise to be conducted in 2013. Article 76 of the Convention on the Law of the Sea calls for coastal nations to submit data and other material concerning the limits of their extended continental shelves to the Commission on the Outer Limits of the Continental Shelf for the commission’s consideration and advice. Although the U.S. has not ratified the Convention on the Law of the Sea, the ECS Project is using the Article 76 guidelines to understand and map where the U.S. could potentially have an extended continental shelf. Arsenault will work with colleagues from the NOAA National Geophysical Data Center (NGDC) and the Department of State to draft the pilot submission for the Western Polygon.
The other team leads who presented regional results were Larry Mayer (University of New Hampshire, Atlantic IRT), Andy Armstrong (NOAA, Arctic IRT), Barry Eakins (NOAA, Central Pacific IRT), and Jennifer Henderson (NOAA, Pacific West Coast IRT).
Topical presentations throughout the week included discussions on “natural prolongation” (a scientific term interpreted within the legal framework of the Convention), sediment fans, seamounts, trenches, the nature of downslope processes, and the use of seismic data for determining sediment thickness. Jason Chaytor (USGS), a member of the Atlantic IRT, presented results from his studies of downslope processes on the Atlantic margin. Mapped features such as landslides and debris flows represent possible areas where a base-of-slope zone may be located.
Deborah Hutchinson (USGS) presented a comprehensive overview of the needs and pitfalls in collecting, processing, and interpreting seismic data and how these data are used to determine sediment thickness, which she illustrated with examples from the Arctic and the Atlantic. Significant seismic data have been collected in the Arctic as part of the ECS Project (for example, see Sound Waves articles at http://soundwaves.usgs.gov/2012/02/, http://soundwaves.usgs.gov/2010/08/, and http://soundwaves.usgs.gov/2009/04/).
Among other contributions, the group benefited from remote participation by Rick Saltus (USGS), Pat Hart (USGS), and representatives of the NGDC and the Bureau of Ocean Energy Management (BOEM). Part of the workshop was dedicated to planning for data needs and future ship time.
The group met again in Washington, D.C., in late June 2012 to review decisions and recommendations from the April technical workshop, engage senior government managers, and construct the roadmap for doing all the remaining work identified in the April workshop.
Additional information about the project and the participating agencies is posted on the ECS Project website (http://www.continentalshelf.gov) and the USGS project website (http://walrus.wr.usgs.gov/research/projects/lawofsea.html).
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