Abstract:
This publication releases swath bathymetry and backscatter datasets derived from multibeam bathymetric data acquired by the U.S. Geological Survey (USGS) on the R/V Marcus G. Langseth legs MGL1108 (transit) and MGL1109 in the Gulf of Alaska, and MGL1111 in the Bering Sea. These data were acquired with a Kongsberg Simrad EM-122 multibeam echosounder and Seafloor Information System (SIS) acquisition software.
The MGL1108 data were combined with the MGL1109 data during processing and are presented as MGL1109.
This data set includes 100-m bathymetry grids generated from processed bathymetry soundings, 100-m backscatter grids generated from coregistered processed backscatter values, extracted center beam bathymetry soundings, and associated metadata. The Gulf of Alaska lines extend from 48.27° N to 57.71° N, 137.81° W to 152.38° W in the northeastern Pacific, including portions of the distal Surveyor and Baranof fan systems, Kodiak-Bowie seamounts, and Aleutian trench near Kodiak Island, AK. The Bering Sea lines extend from 54.04° N to 58.88° N, 166.56° W to 174.04° E, including portions of the Umnak Plateau northwest of Dutch Harbor, AK, central Aleutian Basin, distal eastern flank of Shirshov Ridge, and north face of Bowers Ridge.
These surveys were designed primarily for acquisition of multichannel seismic-reflection imaging and ocean-bottom seismometer OBS velocity analysis in support of Extended Continental Shelf (ECS) maritime zone definition. The USGS activities in mapping the ECS are coordinated through the interagency ECS Task Force, comprising representatives from the U.S. Department of State, the USGS, the National Oceanographic and Atmospheric Administration (NOAA), and several other governmental agencies. Further information on the U.S. Extended Continental Shelf (ECS) Project and its activities is posted at
https://www.state.gov/e/oes/ocns/opa/ecs/index.htm.
In June 2011, the U.S. Geological Survey (USGS) conducted a research cruise in the Gulf of Alaska aboard the R/V Marcus G. Langseth (Lamont-Doherty Earth Observatory, Columbia University) as part of the U.S. Extended Continental Shelf Project. The mission focused primarily on obtaining geophysical data (multichannel and CHIRP seismic reflection, ocean bottom seismometry, multibeam bathymetry, sonobuoy, XBT and XCTD) for the purposes of determining geologic framework, crustal nature, and sediment thickness in support of delineating the U.S. Extended Continental Shelf under provisions contained in Article 76 of the United Nations Convention on the
Law of the Sea (UNCLOS).
Supplemental_Information:
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: environment
Theme_Keyword: geoscientificInformation
Theme_Keyword: oceans
Theme:
Theme_Keyword_Thesaurus: Data Categories for Marine Planning
Theme_Keyword: Bathymetry and Elevation
Theme_Keyword: Substrate
Theme_Keyword: Physical Habitats and Geomorphology
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: seismic reflection methods
Theme_Keyword: multibeam sonar
Theme_Keyword: bathymetry
Theme_Keyword: bathymetry measurement
Theme_Keyword: sea-floor characteristics
Theme_Keyword: marine geophysics
Theme_Keyword: sea-floor acoustic reflectivity
Theme_Keyword: image mosaics
Theme_Keyword: geospatial datasets
Theme:
Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords
Theme_Keyword: marine geophysics
Theme_Keyword: seismic methods
Theme_Keyword: multibeam echo sounder
Theme_Keyword: continental shelf
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Coastal and Marine Hazards and Resources Program
Theme_Keyword: CMHRP
Theme_Keyword: Pacific Coastal and Marine Science Center
Theme_Keyword: PCMSC
Theme_Keyword: backscatter intensity
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:55d23737e4b0518e35468abd
Place:
Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: Gulf of Alaska
Place_Keyword: Bering Sea
Place_Keyword: Kodiak Island
Place_Keyword: Dutch Harbor
Place:
Place_Keyword_Thesaurus: NGA GEOnet Names Server (GNS)
Place_Keyword: Baranof Fan
Place_Keyword: Shirshov Ridge
Place_Keyword: Kodiak Seamount
Place_Keyword: Bowie Seamount
Place_Keyword: Aleutian Trench
Place_Keyword: Umnak Plateau
Place_Keyword: Aleutian Basin
Place_Keyword: Bowers Ridge
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Surveyor Fan
Place_Keyword: Extended Continental Shelf
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator of the dataset and in products derived from these data. This information is not intended for navigation purposes.
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