The bathymetric map of the northern Bering Sea region, plate 1 of USGS Professional Paper 759-B, 1976, was generated using published National Ocean Service maps and an unpublished map from Univ. of Washington. The region covered by the map includes the eastern tip of the Chukotka Peninsula, Russia, east to the Seward Peninsula and northern Yukon Delta, Alaska, and south to St. Lawrence Island, Alaska. The portion digitized was west of the Exclusive Economic Zone (EEZ, or Convention Line of 1867). Only the Russian side of the map was included in the coverage because better data were available for the U.S. side of region from the National Ocean Service, National Geophysical Data Center.

Two bathymetric maps were developed by the U.S. Geological Survey, one for the Chukchi Sea and Arctic Ocean, and one for the Aleutian Trench and Bering Sea. The 2 maps overlap near the Bering Strait. Bathymetric contours were generated from several published sources. It is unclear whether new soundings were collected for these maps. The northern map extends from Wrangel Island, Russia to MacKenzie Bay, Canada, and north to 76 N latitude. The southern map extends from Shelikof Bay, Russia, to the western tip of the Alaska Peninsula, USA, and south to 48 N latitude. Bathymetric contours are at 400 meter intervals with 20, 30, 40, 50, 100, and 200 meter contours added. Contours above 50 meters are rare, and never along the Russian coast. Hard-copy maps were published by the USGS in 1976 and digitized by the Alaska Science Center in 1997. In digital format, the 2 maps have been connected where they overlap in the Bering Strait.

Bathymetric contours were generated from soundings collected during surveys and cruises by the Hydrographic Office, National Ocean Survey, and Coast and Geodetic Survey. The region covered by the map is the Bering Sea Shelf from Bristol Bay, Alaska to the Gulf of Anadyr, Russia. Bathymetry is in meters at 10 m intervals, with 5 m supplemental contours. The digitized portion includes the Anadyr Gulf and Bering Strait in Russian waters (west of the Exclusive Economic Zone), to supplement digitized National Ocean Service maps of U.S. waters (Coastal Shelf Bathymetry of the Bering, Chukchi, and Beaufort Seas). The original paper map was produced by the Geological Society of America and published in 1974. The map is no longer in print from the Geological Society of America (3300 Penrose Place, Boulder, CO 80301) but may be available at natural resource agency libraries that include literature on Alaska and/or Russia. In 1997, the USGS digitized the bathymetric contours for research purposes.

Bathymetric contours were generated from soundings collected by National Ocean Service vessels from ~1900 to ~1971. The 1:250,000 maps are available for U.S. coastal waters. Bathymetric contours are in meters, with 10 meter intervals out to 200 m, supplemented by 2 m contours. Beyond 200 m, contours are at 50 m intervals to maximum depth. The GIS database derived from these maps includes the Bering, Chukchi, and Beaufort Seas in western and northern Alaska (~100 maps).

Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-4-75-BS in Bering Sea, Aleutian Basin, Alaska from 09/07/1975 to 09/18/1975, http://walrus.wr.usgs.gov/infobank/l/l475bs/html/l-4-75-bs.meta.html These data are reformatted from space-delimited ASCII text files located in the Coastal and Marine Geology Program (CMGP) InfoBank field activity catalog at http://walrus.wr.usgs.gov/infobank/l/l475bs/html/l-4-75-bs.bath.html, http://walrus.wr.usgs.gov/infobank/l/l475bs/html/l-4-75-bs.grav.html, and http://walrus.wr.usgs.gov/infobank/l/l475bs/html/l-4-75-bs.mag.html into MGD77T format provided by the NOAA's National Geophysical Data Center(NGDC). The MGD77T format includes a header (documentation) file (.h77t) and a data file (.m77t). More information regarding this format can be found in the publication listed in the Cross_reference section of this metadata file.

Bathymetric contours were generated from soundings collected during geophysical surveys conducted by the USGS from 1969 to 1982, and supplemented by data from other sources. The region covered by the map is the Chukchi Sea from the Bering Strait north to the Arctic Ocean, and Point Barrow, Alaska west to Herald Island, Russia. The map stops just east of Wrangel Island, Russia. Bathymetry is in meters, including 10 meter contour intervals from 10 to 100 meters, and 100 meter contour intervals at depths greater than 100 meters.

Sediment thickness information for the Aleutian and Bowers Basins in the Bering Sea comes from single-channel and multichannel seismic reflection data from 15 cruises that surveyed the Aleutian and Bowers Basins and the intervening Bowers Ridge. Seismic horizons were picked on peak reflection amplitudes, on reflection seismic data sampled at 4 milliseconds, using KingdomSuite seismic interpretation software. One text file (BeringSea-KingdomSuiteNav-2017Dec19.csv) in CSV (comma-separated values) format is a complete navigation file, containing seismic trace positions for all of the seismic lines in the KingdomSuite project, including for seismic lines and segments of seismic lines where seismic horizons were not picked due to poor data quality or location outside of the compilation area. Two other CSV files contain seismic horizon picks in two-way traveltime (TWT). The first CSV file (BeringSeaHorizonPicks-SedimentInterval-2017Dec19.csv) contains picks of the seabed and the top of igneous basement, along with derived values of the interval TWT of the intervening sediment and the thickness of the sediment based on a TWT-to-thickness relationship developed from stacking velocities of the high-quality, long-streamer multichannel seismic reflection cruise MGL1111 in the Aleutian Basin. The second CSV file (BeringSeaHorizonPicks-MinimumSedimentInterval-2017Dec19.csv) contains information where the basement reflection is beyond the maximum TWT of the seismic record; this file tabulates the TWT of the seabed pick, the record length (9 seconds in all cases), and the interval TWT and thickness values of the minimum sediment thickness based on the knowledge that the basement must be deeper than detectable with those records. This situation occurred for 3 seismic cruises (F187, F286, and F386) where they crossed thick sediments immediately north of Bowers Ridge. A raster grid of sediment thickness in GeoTIFF format (AleutianBowersBasins-SedimentThicknessGrid.tif) was created where seismic horizon picks were of sufficient spatial density to create a gridded model. Because the seismic line orientation was unfavorable for gridding in areas where sediments were thickest (north of Bowers Ridge) and thinnest (atop Bowers Ridge), a CSV file of manually determined minimum and maximum sediment thickness constraints (AleutianBowersBasins-SedimentThickness-ManualConstraints.csv) was used to guide the gridding algorithm to minimize gridding artifacts related to line orientation in these areas. These manual constraints are points selected between the seismic survey lines, with assigned thickness values that guide the gridding algorithm to output grid values consistent with the regional sediment thickness trends, as defined by the seismic lines in the Bowers Ridge region. In addition, a masking polygon file (AleutianBowersBasins-GridPolygon.shp) in shapefile format was used to output gridded values only where input data were sufficient for gridding. Each data file, along with a corresponding CSDGM FGDC-compliant metadata file, is provided in its own zip archive file.

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.

This raster dataset represents approximately 69,060 square kilometers of Simrad EM122 multibeam-bathymetry data collected in the Gulf of Alaska during U.S. Geological Survey - Coastal and Marine Geology Program cruise MGL1109 aboard the R/V Marcus G. Langseth. The data have been reduced for position, elevation, orientation, water-column sound-speed, and refraction effects.

A raster grid of sediment thickness in GeoTIFF format (BeringSeaBasins-SedimentThicknessGrid.tif) of the Aleutian, Bowers, and Komandorsky Basins was created by merging GeoTIFF grids of the Aleutian and Bowers Basins and of the Komandorsky Basin, provided in other sections of this data release. The raster grid file, along with a corresponding CSDGM FGDC-compliant metadata file, is provided in a zip archive file.