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Metadata, Frequently-anticipated questions

Seismic reflection and refraction data acquired in Canada Basin, Northwind Ridge and Northwind Basin, Arctic Ocean in 1988, 1992 and 1993.

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Metadata

Metadata also available as HTML, ASCII text and XML.

Frequently-anticipated questions:

What does this data set describe?

Title:
Seismic reflection and refraction data acquired in 1988, 1992, and 1993 in the Canada Basin, Northwind Ridge, and Northwind Basin, Arctic Ocean; USGS Open-File Report
Abstract:
Seismic reflection and refraction data were collected in generally ice-covered waters of the Canada Basin and the eastern part of the Chukchi Continental Borderland of the Amerasia Basin, Arctic Ocean, during the late summers of 1988, 1992, and 1993. The data were acquired from a Polar class icebreaker, the U.S. Coast Guard Cutter Polar Star, using a seismic reflection system designed by the U.S. Geological Survey (USGS). The northernmost data extend to 78° 48' N latitude.

In 1988, 155 km of reflection data were acquired with a prototype system consisting of a single 195 cubic inch air gun seismic source and a two-channel hydrophone streamer with a 150-m active section. In 1992 and 1993, 500 and 1,900 km respectively of seismic reflection profile data were acquired with an improved six air gun, 674 to 1303 cubic inch tuned seismic source array and the same two-channel streamer. All data were recorded with a DFS-V digital seismic recorder. A 12-channel streamer with a 150-m active section was also used to record some data in 1993. Processed sections feature high quality vertical incidence images to more than 6 km of sub-bottom penetration in the Canada Basin.

Refraction data were acquired with U.S. Navy sonobuoys recorded simultaneously with the seismic reflection profiles. In 1988 eight refraction profiles were recorded with the single air gun, and in 1992 and 1993 a total of 47 refraction profiles were recorded with the six air gun array. The sonobuoy refraction records, with offsets up to 35 km, provide acoustic velocity information to complement the short-offset reflection data.

The report includes trackline maps showing the location of the data, as well as both digital data files (SEG-Y) and images (TIFF and JPEG) of all of the profiles.

Supplemental_Information:
Information for USGS Coastal and Marine Geology related activities are online at: <http://walrus.wr.usgs.gov/>
  1. How should this data set be cited?

    Arthur Grantz, Patrick E. Hart, and Steven D. May, 2004, Seismic reflection and refraction data acquired in 1988, 1992, and 1993 in the Canada Basin, Northwind Ridge, and Northwind Basin, Arctic Ocean; USGS Open-File Report.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -165.00000
    East_Bounding_Coordinate: -137.00000
    North_Bounding_Coordinate: +79.00000
    South_Bounding_Coordinate: +71.00000

  3. What does it look like?

    <http://pubs.usgs.gov/of/2004/1243/rjpg/93-04rp.html> (JPEG)
    An example seismic reflection Line 93-04

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 01-Aug-1988
    Ending_Date: 01-Oct-1993
    Currentness_Reference: none

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form:
    Text report containing graphical map images and geophysical data images (no spatial referencing).

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

    2. What coordinate system is used to represent geographic features?

      The map projection used is Lambert Azimuthal.

      Projection parameters:
      Straight-Vertical_Longitude_from_Pole: -155.0
      Standard_Parallel: 90.0
      False_Easting: 0.0
      False_Northing: 0.0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.00001
      Ordinates (y-coordinates) are specified to the nearest 0.00001
      Planar coordinates are specified in degrees

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    Locations of data profiles are shown as color-coded map images at an unspecified projection and scale. These map images are rendered in Scalable Vector Graphics (SVG). The images of the reflection and refraction profiles are rendered in TIFF and JPEG image formats.
    Entity_and_Attribute_Detail_Citation: none

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

    • Arthur Grantz, Patrick E. Hart, and Steven D. May

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Patrick E. Hart
    United States Geological Survey (USGS)
    Geophysicist
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5160 (voice)
    phart@usgs.gov

Why was the data set created?

These data are intended for science researchers, policy makers, and the general public.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 2004 (process 1 of 4)
    Refer to report section "Data processing and archive" for full details of geophysical data processing sequences

    Person who carried out this activity:

    Patrick E. Hart
    United States Geological Survey (USGS)
    Geophysicist
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5160 (voice)
    phart@usgs.gov

    Date: 2004 (process 2 of 4)
    Plotted tracklines of seismic reflection profiles using GMT to create Figure 4. Converted plot to Adobe SVG Viewer file to allow mouse over trackline details and links to profile displays.

    Date: 2004 (process 3 of 4)
    Plotted tracklines of sonobuoy refraction profiles using GMT to create Figure 5. Converted plot to Adobe SVG Viewer file to allow mouse over trackline details and links to profile displays.

    Date: 2004 (process 4 of 4)
    Plotted shot point map of cruises using GMT to create Figure 10. Broke area into three sections for better viewing. Converted plots to Adobe Acrobat PDF files for zooming in on sections.

    Person who carried out this activity:

    Jon R. Childs
    United States Geological Survey (USGS)
    Geophysicist
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5195 (voice)
    jchilds@usgs.gov

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    Data have not been independently verified.

  2. How accurate are the geographic locations?

    100.0 meters

  3. How accurate are the heights or depths?

    Depths are referenced to sea level

  4. Where are the gaps in the data? What is missing?

    Reference the full report for a description of data coverage.

  5. How consistent are the relationships among the observations, including topology?

    Undetermined

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_Constraints:
These data are not intended for navigational purposes. Please recognize the U.S. Geological Survey (USGS) as the source of this information.

  1. Who distributes the data set? (Distributor 1 of 1)

    United States Geological Survey (USGS)
    Box 25286
    Denver, CO 80225
    USA

    (888)ASK-USGS (voice)

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    Please recognize the U.S. Geological Survey (USGS) as the source of this information.

    USGS-authored or produced data and information are in the public domain.

    Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, these data and information are provided with the understanding that they are not guaranteed to be usable, timely, accurate, or complete. Users are cautioned to consider carefully the provisional nature of these data and information before using them for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user.

    Neither the U.S. Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any data, software, information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights.

    Trade, firm, or product names and other references to commercial products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 10-Aug-2003
Metadata author:
Jonathan R. Childs
United States Geological Survey (USGS)
Geophysicist
USGS, MailStop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA

(650) 329-5195 (voice)
jchilds@usgs.gov

Metadata standard:
Content Standard for Digital Geospatial Metadata ("CSDGM version 2") (FGDC-STD-001-1998)

Generated by mp version 2.8.12 on Mon Jun 07 16:43:43 2004
Open-File Report 2004-1243 Home Page Coastal and Marine Geology Home Page

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last modified May 7, 2009 (mfd)

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