Seismic reflection-tracklines, shotpoints, and profile images collected in the Belfast Bay, Maine pockmark field using an EdgeTech SB-424 subbottom profiler during USGS field activities 2006-024-FA and 2009-037-FA (Esri polyline, and point shapefiles, WGS 84, and JPEG images)

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Frequently anticipated questions:

What does this data set describe?

Title:
Seismic reflection-tracklines, shotpoints, and profile images collected in the Belfast Bay, Maine pockmark field using an EdgeTech SB-424 subbottom profiler during USGS field activities 2006-024-FA and 2009-037-FA (Esri polyline, and point shapefiles, WGS 84, and JPEG images)
Abstract:
The U.S. Geological Survey, Woods Hole Coastal and Marine Science Center in cooperation with the University of Maine mapped approximately 50 square kilometers of the seafloor within Belfast Bay, Maine. Three geophysical surveys conducted in 2006, 2008 and 2009 collected swath bathymetric (2006 and 2008) and chirp seismic reflection profile data (2006 and 2009). The project characterized the spatial, morphological and subsurface variability of the Belfast Bay, Maine pockmark field. Pockmarks are large seafloor depressions that are associated with seabed fluid escape.
Supplemental_Information:
These data were collected during three separate surveys: Field Activity 2006-024-FA, 12-17 Sept, 2006 https://cmgds.marine.usgs.gov/fan_info.php?fan=2006-024-FA Field Activity 2008-024-FA, 17-24 Sept, 2008 https://cmgds.marine.usgs.gov/fan_info.php?fan=2008-024-FA Field Activity 2009-037-FA, 27-30 July, 2009 https://cmgds.marine.usgs.gov/fan_info.php?fan=2009-037-FA
The EdgeTech 424 seismic system became inoperable at the beginning of survey 2008-024-FA, although the survey continued collecting interferometric and sidescan sonar data. The third survey in 2009 (2009-037-FA) was conducted to collect just seismic data that was not collected during 2008-024-FA.
  1. How might this data set be cited?
    U.S. Geological Survey, 20201210, Seismic reflection-tracklines, shotpoints, and profile images collected in the Belfast Bay, Maine pockmark field using an EdgeTech SB-424 subbottom profiler during USGS field activities 2006-024-FA and 2009-037-FA (Esri polyline, and point shapefiles, WGS 84, and JPEG images): data release DOI:10.5066/P90QQCOR, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Andrews, Brian D., Danforth, William W., Brothers, Laura L., and Barnhardt, Walter A., 2020, High-resolution geophysical data collected in the Belfast Bay, Maine pockmark field in 2006, 2008, and 2009 by the U.S. Geological Survey: data release DOI:10.5066/P90QQCOR, U.S. Geological Survey, Reston, Virginia.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Andrews, B.D., Danforth, W. W., Brothers, L.L., Barnhardt, W. A., 2020, High-resolution geophysical data collected in the Belfast Bay, Maine Pockmark Field in 2006, 2008, and 2009 by the U.S. Geological Survey: U.S. Geological Survey data release, https://doi.org/10.5066/P90QQCOR
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -68.968692
    East_Bounding_Coordinate: -68.879720
    North_Bounding_Coordinate: 44.431183
    South_Bounding_Coordinate: 44.311247
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5f5f964482ce3550e3bff23f?name=BelfastBay_EdgeTech_424_tracklines_browse.jpg (JPG)
    Thumbnail image of seismic tracklines collected in Belfast Bay, Maine.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 12-Sep-2006
    Ending_Date: 30-Jul-2009
    Currentness_Reference:
    data were collected on the following dates: 20060912-20060917 (Julian day 255-260); 20090727-20090730 (Julian day 208- 211).
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (122)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is WGS 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    BelfastBay_Edgetech_424_tracklines
    SB-424 tracklines for surveys 2006-024-FA and 2009-037-FA (122 polyline features). (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    Line
    Name of the trackline along which seismic-reflection data were collected in the format: LineNumberFileNumber (i.e.'l1f1') (Source: U.S. Geological Survey) Character set
    JD
    Julian day the line was collected representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set
    imagename
    Jpeg image name of seismic-reflection profile corresponding to survey line. Duplicate imagenames exist because both surveys using the same naming convention, however, the SurveyID attribute used with the imagename attribute will provide unique imagenames to correlate with the seismic profiles in jpg format. (Source: U.S. Geological Survey) Character set
    Length_km
    Length of seismic-reflection data line in kilometers (UTM Zone 19N, WGS 84) calculated using ArcGIS Pro. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.283
    Maximum:7.246
    Units:kilometers
    Resolution:0.001
    SurveyID
    WHCMSC field activity identifier (e.g. "2006-024-FA" where 2006 is the survey year, 024 is survey number of that year, and FA is Field Activity). (Source: U.S. Geological Survey) Character set
    DeviceID
    Sonar device used to collect seismic-reflection data. (Source: U.S. Geological Survey) Character set
    VehicleID
    Survey vessel name. (Source: U.S. Geological Survey) Character set
    BelfastBay_Edgetech_424_100sht
    SB-424 100 shot points for surveys 2006-024-FA and 2009-037-FA (7,745 point features). (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    East
    East coordinate in UTM 19 WGS 84 coordinate system (Source: U.S. Geological Survey)
    Range of values
    Minimum:502493.32
    Maximum:509578.32
    Units:meters
    Resolution:0.01
    North
    North coordinate in UTM 19 WGS 84 coordinate system (Source: U.S. Geological Survey)
    Range of values
    Minimum:4906445.30
    Maximum:4919769.32
    Units:meters
    Resolution:0.01
    Lon
    Longitude coordinate in WGS 84 using decimal degrees (Source: U.S. Geological Survey)
    Range of values
    Minimum:-68.879720
    Maximum:-68.968692
    Units:decimal degrees
    Resolution:0.00001
    Lat
    Latitude coordinate in WGS 84 using decimal degrees (Source: U.S. Geological Survey)
    Range of values
    Minimum:44.311247
    Maximum:44.431183
    Units:decimal degrees
    Resolution:0.00001
    FileName
    Name of the trackline along which seismic-reflection data were collected in the format: LineNumberFileNumber (i.e.'l1f1'). Duplicate filenames exist between the two surveys. The combination of "FileName" and "SurveyID" will provide unique records. (Source: U.S. Geological Survey) Character set
    Image
    Jpeg image name of seismic-reflection profile corresponding to survey line. Duplicate image names exist between the two surveys. The combination of "Image" and "SurveyID" will provide unique records. (Source: U.S. Geological Survey) Character set
    Shotnum
    seismic shot number of first, last, and every 100th shot. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1
    Maximum:11601
    Units:shot
    Resolution:1
    Year
    Calendar year data were collected in the format YYYY (Source: U.S. Geological Survey)
    Range of values
    Minimum:2006
    Maximum:2009
    Units:year
    Resolution:1
    JD
    Julian day the line was collected representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey)
    Range of values
    Minimum:208
    Maximum:259
    Units:Julian day
    Resolution:1
    Time
    Time the shot was sampled in the format HH:MM:SS using Universal Coordinated Time (UTC) (Source: U.S. Geological Survey) Character set
    JDTime
    Date and time the shot was sampled. For example 208-12:51:20 is in the format JD-HH:MM:SS using the Julian day and Universal Coordinated Time (UTC) (Source: U.S. Geological Survey) Character set
    JD
    Julian day the line was collected representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey)
    Range of values
    Minimum:208
    Maximum:259
    Units:Julian day
    Resolution:1
    SurveyID
    WHCMSC field activity identifier (e.g. "2006-024-FA" where 2006 is the survey year, 024 is survey number of that year, and FA is Field Activity). (Source: U.S. Geological Survey) Character set
    DeviceID
    Sonar device used to collect seismic-reflection data. (Source: U.S. Geological Survey) Character set
    VehicleID
    Survey vessel name. (Source: U.S. Geological Survey) Character set
    BelfastBay_Edgetech_424_nav.csv
    SB-424 unique navigation for surveys 2006-024-FA and 2009-037-FA (127,771 records including the header). (Source: U.S. Geological Survey)
    BelfastBay_Edgetech_424_images.zip
    zip file containing the seismic profile images in two folders (06024 and 09037). Folder 06024 contains 56 jpg images and folder 09037 contains 66 jpg images (Source: U.S. Geological Survey)
    Entity_and_Attribute_Overview:
    Each polyline feature in this shapefile can be associated with a JPG image in ArcGIS (see the BelfastBay_Edgetech_424_Images.zip archive accompanying BelfastBay_Edgetech_424_meta.xml available from the larger work citation). The fist, last, and multiple of 100 shot features in BelfastBay_Edgetech_424_100sht.shp (available from the larger work citation) correspond to the x-axis ticks on the JPG images.
    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)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov

Why was the data set created?

This dataset contains seismic shotpoint and trackline navigation, as well as seismic profile images for approximately 450 km of chirp seismic-reflection data collected by the U.S. Geological Survey in Belfast Bay, Maine. This information allows for spatial correlation of chirp seismic-reflection profiles images with other geophysical and sample data for investigating the morphology and stratigraphy in the area.

How was the data set created?

  1. From what previous works were the data drawn?
    SEG-Y SB-424 data (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, raw segy data.

    Type_of_Source_Media: disc
    Source_Contribution:
    The EdgeTech SB-424 subbottom profiler towfish (4-24 kHz) was towed from a starboard side davit on the R/V Rafael with the transducer approximately 1 meter below the water line, and 2.5 meters astern of the DGPS antenna mounted atop the port side of the cabin roof. Navigation data for the SB-424 were collected using a Hemisphere R131 Differential GPS (DGPS) receiver. Edgetech Discover v2.0 seismic acquisition software was used to control the Geo-Star FSSB topside unit, digitally log the envelope data in the SEG-Y Rev. 1 format (IEEE floating point), and record GPS navigation coordinates to the SEG-Y trace headers (in arc minutes of Latitude and Longitude, divided by a scalar of 10,000). Data were acquired using 250 ms shot rate, with a 1-ms pulse length and a 4 to 24 kHz frequency sweep. Recorded trace lengths were approximately 200 ms.
  2. How were the data generated, processed, and modified?
    Date: Jul-2009 (process 1 of 2)
    STEP 1. PROCESS SEG-Y FILES
    Note: Processing step 1 described here are the same for both of the surveys that collected seismic reflection data (2006-024-FA, and 2009-037-FA)the processing date reflects the most recent (2009) date.
    Scripps Institute of Oceanography SIOSEIS and Colorado School of Mines Seismic Unix software was used to process SEG-Y data, extract navigation data, and create JPEG images of the seismic profiles. The processing flows and scripts used are summarized below in the following processing steps.
    1) The SIOSEIS script sio_renum read the raw SEG-Y files, with the envelope-detected trace, renumbered shots starting from one, and wrote out new SEG-Y files. The original shot numbers, which were assigned by Discover sequentially over the duration of the entire acquisition session despite SEG-Y file changes, are preserved in the raw SEG-Y data.
    2) The SIOSEIS script siothresh_pltwbt (which runs the sio_threshwbt script) was used to predict water-bottom times from the envelope SEG-Y traces in each file and write the predicted two-way travel times for the seafloor to a '*.wbt.csv' file. New swell filtered SEG-Y files which are corrected for ship's heave motion were created by statically shifting the difference between water-bottom picks and smoothed water-bottom picks .
    3) Seismic Unix (version 4.2) script read424_hc was used to read the swell filtered SEG-Y files, write a Seismic Unix file, and extract SEG-Y trace header information, including shot number, longitude, latitude, year, Julian day, and time of day (UTC). Header information from each SEG-Y file was saved to text files after an AWK (no version) filter was used to maintain the first and last shots, shots at multiples of 100, and shots with unique navigation coordinates. Geographic coordinates (WGS 84) were converted to UTM zone 19 N coordinates (WGS 84) using Proj (version 4.6.0). End shots and shots at multiples of 100 may not have unique navigation coordinates. The unique navigation was output to two different files: "RAFA06024_UniqueSht.csv" and "RAFA09037_UniqueSht.csv" and then merged into "BelfastBay_EdgeTech_424_nav.csv." The 100 shot navigation was output to "RAFA06024_100Sht.csv" and "RAFA09037_100Sht.csv."
    4) Seismic Unix (version 4.2)script plot424_hc was used to read all the swell filtered SEG-Y files and plot the data as 8-bit gray-scale Postscript files using the Seismic Unix 'psimage' algorithm. The profiles contain 80 milliseconds of two-way travel time within a 14-inch vertical window, yielding approximately 5.7 milliseconds per inch. Postscript images were converted to JPEG format using ImageMagick. The x-axis units of the images are shot number while the y-axis is two-way travel time in seconds (note: extremely short lines may not display a complete x-axis in these images).
    The contact person for this and all subsequent processing steps below is Brian Andrews. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Brian Andrews
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov
    Date: 2016 (process 2 of 2)
    STEP 2. CONVERT NAVIGATION TO SHAPEFILE
    The navigation files in csv format from previous step were converted to point and polyline shapefile using ArcMap (v. 10).
    Tracklines: RAFA06024_UniqueSht.csv and RAFA09037_UniqueSht.csv were each converted to a point shapefiles using the "Create Feature Class from XY Table" context menu in ArcCatalog, and then merged into one shapefile (BelfastBay_UniqueSht.shp) using the Geographic coordinate system (WGS 84). The merged point shapefile was then converted to a polyline shapefile (BelfastBay_EdgeTech_424_tracklines.shp) using the "Points to Line" tool.
    Shotpoints: RAFA06024_100Sht.csv and RAFA09037_100sht.csv were each converted to a point shapefile using the "Create Feature Class from XY Table" context menu in ArcCatalog. The individual 100 shot shapefiles were merged into one point shapefile (BelfastBay_EdgeTech_424_100sht.shp) using the merge tool.
    The following string attributes were added and populated in the attribute table of trackline and 100 shot shapefiles "SurveyID, DeviceID, and VehicleID."
  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?
  2. How accurate are the geographic locations?
    Positioning data were recorded using Edgetech Discover V2.0 acquisition software, which logged geographic coordinates to individual trace headers SEG-Y data format. A conservative estimate of DGPS horizontal positional accuracy is within 2 m; the layback position of the transducer relative to the DGPS antenna was accounted for during acquisition.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    data were collected on the following dates: 20060912-20060917 (Julian day 255-260); 20090727-20090730 (Julian day 208- 211).
  5. How consistent are the relationships among the observations, including topology?
    Chirp seismic-reflection data were collected during two of the three geophysical surveys conducted in Belfast Bay, ME. The shapefile 'BelfastBay_EdgeTech_424_100sht.shp' contains the first, last, and 100-interval shotpoints for all seismic tracklines. The attribute fields 'FileName' and 'imagename' for each polyline feature in 'BelfastBay_EdgeTech_424_tracklines.shp' correspond to the JPG profile images in "BelfastBay_EdgeTech_424_images.zip." The zip file BelfastBay_Edgetech_424_images.zip contains the folders "06024" and "09037." One JPG image exists for each feature. Processed seismic data were converted to JPG image format for ease of seismic trace display. Quality control was conducted during acquisition.

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:
Public domain data from the U.S. Government are freely re-distributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. These data are not to be used for navigation.
  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
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? This data release includes the shapefile BelfastBay_Edgetech_424_Tracks.shp, the browse graphic BelfastBay_Edgetech_424_Tracks.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file BelfastBay_Edgetech_424_Tracks_meta.xml
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    To utilize these data, the user must have software capable of reading shapefile format, or GIS software capable of utilizing web mapping or feature services.

Who wrote the metadata?

Dates:
Last modified: 10-Dec-2020
Metadata author:
Brian Andrews
U.S. Geological Survey, Northeast Region
Geographer
384 Woods Hole Road
Woods Hole, MA

508-548-8700 ext. 2348 (voice)
bandrews@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P90QQCOR/BelfastBay_EdgeTech_424_meta.faq.html>
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