Multibeam bathymetry data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA

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Frequently anticipated questions:


What does this data set describe?

Title:
Multibeam bathymetry data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA
Abstract:
Multibeam bathymetry data were collected along the Queen Charlotte-Fairweather Fault between Icy Point and Dixon Entrance, offshore southeastern Alaska from 2016-05-17 to 2016-06-12. Data were collected aboard the Alaska Department of Fish and Game R/V Medeia using a Reson SeaBat 7160 multibeam echosounder, Reson 7k Control Center, and HYPACK. This data release contains approximately 4,600 square kilometers of multibeam bathymetry and backscatter data, organized into zip files for each Julian Day of the survey.
Supplemental_Information:
Additional information about the field activities from which these data were derived is available online at:
http://compass.er.usgs.gov/fan_info.php?fan=2016-625-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Balster-Gee, Alicia F., Andrews, Brian D., Brothers, Daniel S., Uri S. ten Brink, Kluesner, Jared W., and Haeussler, Peter J., 2017, Multibeam bathymetry data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA: data release DOI:10.5066/F7NG4PTW, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Balster-Gee, Alicia F., Brothers, Daniel S., Andrews, Brian D., Uri S. ten Brink, Kluesner, Jared W., and Haeussler, Peter J., 2017, Multibeam bathymetry and backscatter data and multichannel sparker seismic-reflection data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA: data release DOI:10.5066/F7NG4PTW, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -136.913215
    East_Bounding_Coordinate: -134.338608
    North_Bounding_Coordinate: 58.023711
    South_Bounding_Coordinate: 55.031169
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5a0a213fe4b09af898c9ef04?name=2016-625-FA_multibeam_index_map.jpg&allowOpen=true (JPEG)
    Thumbnail image of bathymetric terrain model of Queen Charlotte Fault area, southeastern Gulf of Alaska.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 17-May-2016
    Ending_Date: 12-Jun-2016
    Currentness_Reference:
    Ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: ASCII text
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set.
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 8
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -135.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 20.000000
      Ordinates (y-coordinates) are specified to the nearest 20.000000
      Planar coordinates are specified in meters
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: WGS 84
      Altitude_Resolution: 0.1
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    .HSX
    Hypack format for raw sonar files (ASCII format) (Source: Producer defined)
    DFT
    Dynamic Draft (Squat) Correction (Source: Hypack) Three space delimited numbers; the device number (listed in headers), the time lag measured in seconds past midnight, and the draft correction.
    FIX
    Fix (Event) Mark (Source: Hypack) Three space delimited numbers; the device number (listed in headers), the time lag measured in seconds past midnight, and the event number (listed sequentially).
    HCP
    Heave Compensation (Source: Hypack) Five space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, heave in meters, roll in degrees (positive for port side up and negative for starboard side up), pitch in degrees (positive for bow up and negative for stern up).
    EC1
    Echo Sounding (single frequency) (Source: Hypack) Three space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, raw depth (meters).
    GPS
    GPS measurements (Source: Hypack) Eight space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, course over ground (degrees), speed over ground (knots), GPS hdop, GPS mode, number of satellites.
    GYR
    Gyro Data (heading) (Source: Hypack) Three numbers; the device number (listed in headers), time lag measured in seconds past midnight, and ship heading angle.
    POS
    Position (Source: Hypack) Four space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, x value (easting) and y value (northing) (UTM zone 8N).
    PSA
    Pitch Stabilization Angle (Source: Hypack) Five space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, ping number, projector pitch angle (head 0), and projector pitch angle (head 1). Note PSA records follow RMB records when pitch stabilization is active.
    RMB
    Raw Multibeam data (Source: Hypack) Nine space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, sonar type code (listed in headers), sonar flags (listed in headers), available beam data (listed in headers), number of beams to follow, sound velocity (m/sec), and ping number. Immediately following the RMB record is a record containing slant ranges in work units.
    RSS
    Raw Sidescan (Source: Hypack) Thirteen space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, sonar flags (bit coded hexadecimal format), number of samples of the port transducer, number of samples from the starboard transducer, sound velocity (m/sec), ping number, altitiude (m), sample rate (samples/second), minimum amplitude, maximum amplitude, bit shift for byte recording, and frequency (either 0 or 1 for simultaneous dual frequency operation). Immediately following the RSS record are two amplitude samples from the port and starboard, respectively.
    SNR
    Sonar Runtime Settings (Source: Hypack) Six space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, ping number, sonar ID (listed in headers), number of settings to follow (whole number between 1 and 12), and settings listed (values for settings listed).
    TID
    Tide Correction (Source: Hypack) Three space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, and the tide correction (positive or negative number).
    POS
    Position of ship (Source: Hypack) Four space delimited numbers; the device number (listed in headers), the time lag measured in seconds past midnight, and x and y position of the ship from the antenna (northing and easting, UTM zone 8N)
    QUA
    Position quality information (Source: Hypack) Seven space delimited numbers; the device number (listed in headers), the time lag measured in seconds past midnight, number of values to follow, ten minus the horizontal dilution of precision, value for the horizontal dilution of precision, number of satellites, and GPS mode (listed in headers).
    RAW
    Position information (Source: Hypack) Seven space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, number of values to follow, latitude (raw latitude times 100), longitude (raw longitude times 100), antenna altitude above ellipsoid (meters), utc time (format HHMM).
    GYR
    Gyro data (heading) (Source: Hypack) Three space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, and ship heading angle.
    MSG
    Message string (Source: Hypack) Two space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight and a message string beginning with $GPR and ending with $#. The string contains position data sent from the shipboard GPS unit.
    EC1
    Echo Sounding (single frequency) (Source: Hypack) Three space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, and raw depth (meters).
    HCP
    Heave Compensation (Source: Hypack) Five space delimited numbers; the device number (listed in headers), time lag measured in seconds past midnight, heave in meters, roll in degrees (positive for port side up and negative for starboard side up), pitch in degrees (positive for bow up and negative for stern up).
    FIX
    Fix (Event) Mark (Source: Hypack) Five space delimited numbers; the device number (listed in headers), the time lag measured in seconds past midnight, the event number, and x and y position (northing and easting, UTM zone 8N). This fix marks the end of the .RAW navigation file.
    Magnitude
    Magnitude of returned signal (Source: Reson) Magnigude of returned beam signal with a time vaied gain applied to it.
    Phase
    Phase of returned signal (Source: Hypack) Phase of returned beam signal.
    Entity_and_Attribute_Overview:
    HSX files begin with 28 header rows describing collection methods and are followed by data rows. Data rows consist of 12 different data types (listed as attributes above). RAW files begin with 22 header rows and are followed by data rows. Data rows consist of 8 types of data types (listed as attributes above. Reson 7K files are generic data records for the returned beam data consisting of magnitude and phase of the returned beams. These data are organized into separate zip files based on the date of collection (Julian day). Within each Julian Day folder, there are RAW, HSX, and 7K files labeled in the format ###_###_####.*; the first number corresponding to the Julian Day of collection, line number, and UTC time of collection.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Alicia F. Balster-Gee
    • Brian D. Andrews
    • Daniel S. Brothers
    • Uri S. ten Brink
    • Jared W. Kluesner
    • Peter J. Haeussler
  2. Who also contributed to the data set?
    Data was collected aboard Alaska Department of Fish and Game’s R/V Medeia and would not be possible without the support of vessel crew members Jim deLaBruere, Craig Conger, Cedar Stark, and Becky Wilson.
  3. To whom should users address questions about the data?
    Alicia Balster-Gee
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Geophysicist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7581 (voice)
    831-427-4748 (FAX)
    abalster-gee@usgs.gov

Why was the data set created?

The Queen Charlotte-Fairweather Fault (QCFF) is a major structural feature that extends more than 1,200 km from northern Vancouver Island, Canada to the Fairweather Range of southern Alaska. The fault system represents a major transform boundary that separates the Pacific Plate from the North American Plate, and in many ways, can be considered an analog ‘sister’ fault to California’s San Andreas Fault. Early studies in the 1970s and 1980s based on historical marine geophysical data demonstrated that approximately 75 percent of the system is located offshore along the continental shelf-edge and slope, more than 20-50 km from land in eastern Gulf of Alaska. Historical seismicity records dating back to 1890 include dozens of large magnitude earthquakes, including eight events of magnitude greater than 7 and Canada’s largest earthquake on record (1949, M8.1). Finally, two recent earthquakes, a M7.8 in 2012 (“Haida Gwaii earthquake”) and M7.5 in 2013 (“Craig earthquake”) stimulated a substantial amount of scientific study of the QCFF and renewed concern over potential threats to coastal infrastructure and populations residing in southeastern Alaska and northwestern British Columbia. Survey goals included determining how fast the two sides of the fault move past each other (slip rate) and deciphering the historical movement of the fault. We also want to better understand how large earthquakes might trigger potentially dangerous underwater landslides. The purpose of this data is to provide a detailed bathymetric terrain model of a portion of the Queen Charlotte Fault and adjacent seafloor.

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: 20-Jun-2016 (process 1 of 1)
    Data Acquisition multibeam bathymetry data were collected along the Queen Charlotte fault in southeast Alaska using a Reson SeaBat 7160 multibeam sonar operating at a frequency of 44 kHz that was mounted on wing-mount from the starboard side of the R/V Medeia owned and operated by the Alaska Department of Fish and Game. The sonar collected depth, backscatter (time series), and water column data along approximately 4,178 kilometers of survey lines oriented parallel with the gradient of the continental shelf west of Chichagof and Baranof islands in southeast Alaska. Data were collected using the Reson 7k Control Center and HYPACK (v. 2016). Vessel attitude was recorded using an Applanix POS MV 320 V5 to provide attitude and positioning that was mounted on the centerline of the vessel. Speed of sound was recorded at 5-8 hour intervals using a Oceanscience RapidCAST SV system mounted on the starboard quarter. Navigation was recorded using Differential Global Positioning System and a Hemisphere MBX-4 GPS receivers mounted on above the bridge. Data are combined into zip files per Julian Day. Within each zip file there are three file types per transect line. The files are named with an alpha-numeric code in AAA_BBB_CCCC.7K, .HSX, or .RAW format, where AAA is the Julian Day of collection, BBB is the transect line number, and CCCC is the UTC time of collection. Files with the .7K suffix are raw bathymetry data, .HSX are raw bathymetry data with ship motion included, and .RAW are raw navigation data. Person who carried out this activity:
    Doug MacGillivray
    TerraSond LLC
    Survey Technician
    1617 South Industrial Way, Suite 3
    Palmer, AK

    907-745-7215 (voice)
    907-745-7273 (FAX)
    info@terrasond.com
  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?
    Accuracy checks were performed during data collection.
  2. How accurate are the geographic locations?
    +/- 2 meters for the Applanix POS MV positioning system mounted on the centerline of the vessel
  3. How accurate are the heights or depths?
    +/- 15 centimeters for the Applanix POS MV positioning system mounted on the centerline of the vessel
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted.

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:
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.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available for download organized into zip files by Julian Day of collection. Within each zip file there are several HSX, RAW, and 7K files. FGDC-compliant metadata is downloadable separately.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    HSX and RAW files can be viewed with any text editor capable of reading ASCII format including WordPad and Text wrangler, in addition to Caris HIPS and SIPS, SonarWiz, and Qimera. 7K files can be viewed using Fledermaus FMMidwater software or other software described on Teledyne's website (http://www.teledyne-pds.com/wp-content/uploads/2017/06/DATA-FORMAT-DEFINITION-7k-Data-Format-Version-3.07.pdf).

Who wrote the metadata?

Dates:
Last modified: 05-Dec-2017
Metadata author:
Alicia Balster-Gee
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Geophysicist
2885 Mission Street
Santa Cruz, CA
United States of America

831-460-7581 (voice)
abalster-gee@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/2016-625-FA_Multibeam_Metadata.faq.html>
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