Review&Forecast—January 2010 IssueUSGS Support for a National Ocean Policy: From the Coasts to Deep Ocean
By Marcia McNutt
U.S. Geological Survey
One of my first official duties as the 15th director of the U.S. Geological Survey (USGS) is to bring you this report summarizing the USGS's continued commitment to provide science and information that guides our management, use and understanding of coastal and ocean systems. President Barack Obama recently directed all federal ocean agencies to develop and implement a national ocean policy, and I am especially honored to lead the USGS's community of respected scientists in supporting this initiative.
The president's policy calls for a shared response to national challenges spanning energy security, climate change, and economic, public and environmental health. As diverse as these challenges are, progress on all fronts requires a fundamental understanding of the geology and geological processes that define the distribution of hazards, living and nonliving resources, and the vulnerability of complex systems to change. The USGS is the federal science agency responsible for providing that geological characterization of the nation.
Part of our unique role in supporting the president's vision is based on our history, mission and expertise in coastal and marine geological research. USGS research addresses issues spanning natural hazards, environmental health, and energy and mineral resources. Through this research, the USGS has made great strides in 2009 in understanding the following aspects of our dynamic Earth.
Gas Hydrate Exploration
Marine gas hydrate has the potential to be a significant energy resource, but also a threat to seafloor stability and a significant addition to atmospheric greenhouse gases if released catastrophically. Marine gas hydrates are commonly identified by bottom-simulating reflections (BSRs) gathered through remote sensing, but BSRs typically occur in fine-grained sediments containing low-saturation gas hydrate. These low-saturation gas hydrate deposits are not considered to be significant energy resources or hazards.
The USGS, along with industry and federal partners, helped develop a strategy to identify high-saturation marine gas hydrates in coarse-grained sediments independent of BSRs. We applied a petroleum systems approach integrating the presence of geologic reservoirs, sources and transport pathways with advanced seismic attribute analysis. A collaborative 2009 drilling program in the Gulf of Mexico tested this integrated approach and demonstrated for the first time that marine gas hydrates do occur in high saturations in coarse-grained sediments on passive continental margins. This discovery warrants continued field studies and research to better understand the potential of marine gas hydrate systems as resources, hazards and agents of climate change.
Studying Tsunamis and Hazards
The Samoa earthquake and tsunami on September 29, reminded us of our vulnerability to hazards posed by our dynamic Earth. The USGS supports a sustained program to understand, define and quantify these and other hazardous events. A comprehensive viewpoint is needed, as tsunamis can be caused by earthquakes, coastal landslides, submarine landslides and volcanic eruptions, and their hazard potential is highly dependent on the source characteristics, the submarine terrain across which they propagate and the character of the impacted area.
The USGS recently worked in partnership with the Nuclear Regulatory Commission and academic colleagues to produce a special report in Marine Geology titled, 'Tsunami Hazard Along the U.S. Atlantic Coast,' which outlined an assessment of tsunami hazard potential throughout the region. Ongoing USGS research includes field efforts to map and date submarine landslides and tsunami deposits onshore, as well as modeling historic events such as the deadly tsunamis generated by landslides during the 1964 Great Alaskan Earthquake. USGS scientists are also investigating the potential for the Puerto Rico trench to create large tsunamigenic earthquakes that may affect the U.S. East Coast.
Mapping the ECS
The USGS is part of an Interagency Task Force identifying the limits of the U.S. Extended Continental Shelf (ECS) in the Arctic Ocean, and to do so, we are following criteria set forth under the U.N. Convention on the Law of the Sea. These efforts will ultimately define the spatial extent of U.S. sovereign rights over the seafloor and subseafloor beyond 200 nautical miles.
Two seasons of data acquisition using two icebreakers have been completed through collaboration between the USGS and Geological Survey of Canada, with support from NOAA, the U.S. Coast Guard and the U.S. Department of State. In working together and reaching remote areas where surface ships have never surveyed, the icebreaker Coast Guard cutter Healy collected multibeam bathymetric data, and the Canadian coast guard ship Louis S. St-Laurent collected seismic reflection and refraction data.
The data from these missions will not only address the specific requirements of ECS delineation, but also will provide an opportunity to revise models of the origin and evolution of this poorly understood portion of the Arctic Ocean. Our understanding of continental margin and seafloor evolution will be further enhanced by future programs in the Arctic, the Atlantic margin, and the Pacific margin and territories.
Conclusions, Legacies for the Future
The USGS maintains a diverse portfolio of expertise, providing the scientific basis for policy and decision making by the U.S. Department of the Interior, other federal agencies, states and the nation. The USGS is ready and well positioned to meet the president's vision for a comprehensive, ecosystem-based framework for the long-term conservation and use of our ocean and coastal resources for generations of Americans to come.
As we move forward, we are guided by the legacy of one of our own, Bill Normark, who passed away this last year. Bill was driven by an unbounded spirit of inquiry that resulted in substantial contributions to our understanding of geological systems, from the coast to the continental shelf and deep ocean spreading centers. His career was marked by persistence, as witnessed by his seminal contributions to the understanding of turbidite systems, and by an unparalleled ability to apply his deep understanding of geological systems to wide-ranging societal issues. Bill's legacy is an inspiration and guides USGS coastal and marine geology efforts to help society live with and benefit from dynamic coastal and marine systems.