A Proposal to Complete Mapping of the World Ocean Floors

Abstract

We propose an international, collaborative surface-ship-based effort to survey the world's ocean floors in all the areas not yet thoroughly surveyed by swath bathymetric sonar, sidescan sonar and routine geophysics (magnetics, gravity, subbottom profiler) to precise standards of data quality and navigation accuracy. These new bathymetric and associated measurements will gradually replace the existing non-uniform coverage of surface vessel track and area data, currently combined with uniform but low resolution altimeter-derived depths. The objective is to produce a world ocean database at least an order of magnitude better in resolution than what exists over much of the world ocean. Currently, the only established international structure with a worldwide mandate for compiling bathymetric data is GEBCO (General Bathymetric Chart of the Oceans, jointly sponsored by the Intergovernmental Oceanographic Commission of UNESCO and the International Hydrographic Organization). GEBCO continually updates its world ocean maps and grids of depths by incorporating regional maps produced in the IBC (International Bathymetric Chart), localized maps resulting from research projects, data assembled by scientific data groups such as LDEO's Marine Geoscience Data System, track data submitted to world and national data centers, and inshore data collected by Hydrographic Offices for navigational purposes. Further multibeam data is expected to come from Coastal States who have undertaken mapping of their juridical Continental Shelf to satisfy the requirements of UNCLOS Article 76. This acoustic data is combined with satellite altimetry data to produce maps that have a horizontal resolution that is in places hundreds of meters but over extensive areas no better than approximately 28 km. In other words, the fabric of the world ocean floor is known and portrayed to highly variable resolution. This means that while the first-order plate tectonic/volcanic seafloor fabric (fracture zones, rift valleys, large seamounts and igneous plateaus) is captured for the entire ocean, second order features like abyssal hills, fault-controlled escarpments, lava flows, propagating rift tips, volcanic rift zones, deep-sea channels, mud volcanoes, emergent diapirs, landslide scars and debris flows, pockmarks, and iceberg plowmarks are know only in a few limited areas. Although vigorous efforts have produced maps of high resolution in some areas, there is at present no coherent plan to collect data that would bring the rest of the ocean up to the level of knowledge that is achievable. We solicit interest in organizing an international workshop that would produce a long-term plan to measure depths and associated data in a systematic fashion in the vast oceanic regions sparsely surveyed by surface ships. To meet this ambitious objective, this international project will need to be carefully designed to optimize return of information balanced against economical use of ship time. Societal benefits will include improved assessment of seafloor/subbottom geological resources, geohazard risk (earthquakes, tsunamis, volcanism and submarine landslides), fin and shellfish habitats, submarine cable routing, and navigational hazards. Science will gain understanding of the complex processes that shape and modify the ocean floor and subbottom, including the influence of bottom topography on circulation and the seafloor's role as benthic biosphere host. Exciting discoveries will attract follow-up academic studies, e.g. with AUVs, sampling, and sea-floor observatories.

Department

Center for Coastal and Ocean Mapping

Publication Date

12-2008

Volume

Fall Meeting, 2008

Journal Title

American Geophysical Union (AGU)

Conference Date

Dec 15 - Dec 19, 2008

Publisher Place

San Francisco, CA, USA

Publisher

American Geophysical Union Publications

Document Type

Conference Proceeding

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