SEISMICTRACKLINE - Survey lines along which EdgeTech 512i chirp seismic-reflection data were collected by the U.S. Geological Survey in the Cape Ann - Salisbury Beach, MA survey area.

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Frequently-anticipated questions:

What does this data set describe?

Title:
SEISMICTRACKLINE - Survey lines along which EdgeTech 512i chirp seismic-reflection data were collected by the U.S. Geological Survey in the Cape Ann - Salisbury Beach, MA survey area.
Abstract:
These data were collected under a cooperative agreement with the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center. Initiated in 2003, the primary objective of this program is to develop regional geologic framework information for the management of coastal and marine resources. Accurate data and maps of sea-floor geology are important first steps toward protecting fish habitat, delineating marine reserves, and assessing environmental changes due to natural or human impacts. The project is focused on the inshore waters (5-30 m deep) of Massachusetts between the New Hampshire border and Cape Cod Bay. Data collected for the mapping cooperative have been released in a series of USGS Open-File Reports <(<http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html>). This spatial dataset is from the Cape Ann and Salisbury Beach Massachusetts project area. The data collected in two separate surveys in 2004 and 2005 and cover approximately 325 square kilometers of the inner continental shelf. High resolution bathymetry and backscatter intensity were collected in 2004 and 2005. Seismic profile data, sediment samples and bottom photography were also collected in 2005.
  1. How should this data set be cited?

    U.S. Geological Survey, 2008, SEISMICTRACKLINE - Survey lines along which EdgeTech 512i chirp seismic-reflection data were collected by the U.S. Geological Survey in the Cape Ann - Salisbury Beach, MA survey area.: Open-File Report 2007-1373, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Barnhardt, Walter A. , Andrews, Brian D. , Ackerman, Seth D. , Baldwin, Wayne E. , and Hein, Christopher J. , 2008, High-Resolution Geological Mapping of the Inner Continental Shelf: Cape Ann to Salisbury Beach, Massachusetts.: Open-File Report 2007-1373, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.806938
    East_Bounding_Coordinate: -70.594713
    North_Bounding_Coordinate: 42.882736
    South_Bounding_Coordinate: 42.666825

  3. What does it look like?

    <https://pubs.usgs.gov/of/2007/1373/GIS/browse_jpg/SeismicTrackline.jpg> (JPEG)
    EdgeTech 512i trackline navigation offshore of Massachusetts between Cape Ann and Salisbury Beach

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

    Beginning_Date: 08-Sep-2005
    Ending_Date: 20-Sep-2005
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: vector 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 (226)

    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 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      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.

  7. How does the data set describe geographic features?

    SeismicTrackLine
    Trackline for seismic profiles (Source: USGS)

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features

    FileName
    Name of seismic data file (Source: USGS)

    Image
    Name of seismic profile JPEG image used as hyperlink (Source: USGS)

    Year
    Calendar year data were collected (Source: USGS)

    JD
    Julian day data were collected (Source: USGS)

    VehicleID
    Survey vessel name (Source: USGS)

    Length
    Length of seismic profile in kilometers (UTM Zone 19N, WGS84) (Source: USGS)

    SurveyID
    WHSC field activity number (Source: USGS)

    DeviceID
    Sonar device used to collect seismic-reflection data (Source: USGS)

    FID
    Internal feature number (Source: ESRI)

    Sequential unique whole numbers that are automatically generated

    Shape_Leng
    Length of trackline segment in meters (UTM Zone 19N, WGS84) (Source: USGS)

Who produced the data set?

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

  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 02543-1598
    USA

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

Why was the data set created?

This data set contains trackline navigation for approximately 1100 km of EdgeTech 512i chirp seismic-reflection data collected by the U.S. Geological Survey during a 2005 cruise offshore of Massachusetts between Cape Ann and Salisbury Beach.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Source_Contribution:
    Seismic-reflection data acquisition at sea (2005): Chirp seismic data were collected using an EdgeTech Geo-Star FSSB sub-bottom profiling system and an SB-0512i towfish (0.5-12 kHz) on the R/V Connecticut of Groton, CT. Delph Seismic+Plus acquisition software (Triton Elics International Inc.) was used to control the Geo-Star topside unit and digitally log trace data in the SEG-Y rev. 1 standard format. Data were acquired using a 0.25-s shot rate, a 9-ms pulse length, and a 0.5 to 6 kHz frequency sweep. Trace lengths were adjusted to account for changes in water depth, and consequently ranged between 100 and 200 ms. Tracklines are spaced between 100 and 1500 m apart in the shore parallel direction and about 1 km apart in the shore perpendicular direction.

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

    Date: Aug-2007 (process 1 of 4)
    A script was run that used Seismic Unix (version 4.1) to read the SEG-Y files, write a Seismic Unix file, and extract SEG-Y trace header information, which included shot number, longitude, latitude, year, Julian day, and time of day (UTC). Geographic coordinates were converted to UTM zone 19 coordinates using Proj (version 4.6.0). Before saving the header information to a text file, the data were filtered using AWK (no version) to save only unique shot point locations. In addition, a separate text file containing even 500 shot intervals was saved. The 500 shot text file maintains the start and end shots, which may not necessarily be unique fixes. A 500 shot interval was chosen because it corresponds to the annotation interval provided along the top of the seismic-reflection profile JPEG images, which are included in the 'GIS\hyperlink_images' folder.

    Person who carried out this activity:

    Wayne Baldwin
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov

    Date: Aug-2007 (process 2 of 4)
    Text files for each seismic line were concatenated into two comma-delimited text files, one containing unique shot point positions ('SeismicShot_unique.csv', which is provided in the zip-compressed package of the shapefile 'SeismicShot_500.shp'), and another containing the 500 shot intervals.

    Person who carried out this activity:

    Wayne Baldwin
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov

    Date: Aug-2007 (process 3 of 4)
    Both concatenated, comma-delimited text files were imported into ArcMap (version 9.2) and saved as points in ESRI shapefile and file geodatabase feature class formats. During import into the file geodatabase, point positions were projected to meters, UTM, Zone 19, WGS84.

    Person who carried out this activity:

    Wayne Baldwin
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov

    Date: Aug-2007 (process 4 of 4)
    The shapefile containing unique shot point positions was used as an input for VACExtras (version 1.97), a VB collection of tools developed by VeeAnn Cross (USGS-WHSC), which converts point data to a new polyline shapefile, based on record order. The 'LineName' field was used to define which points were used to generate each polyline feature. Using Xtools Pro for ArcGIS desktop (version 4.1.0), the length of each polyline segment was calculated and included in two new attribute fields, 'Length' and 'Shape_Leng', specifying UTM, Zone 19 N, WGS84 kilometers and meters, respectively. Prior to importing a copy of the polyline shapefile into the file geodatabase to create a file geodatabase feature class, the 'Shape_Leng' attribute field was deleted because it was automatically replaced and recalculated with identical name and units (meters); During import into the file geodatabase, polyline features were projected to meters, UTM, Zone 19, WGS84.

    Person who carried out this activity:

    Wayne Baldwin
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov

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

    Stockwell, John, 2008, CWP/SU: Seismic Uni*x: Center for Wave Phenomena - Colorado School of Mines, Golden, CO.

    Online Links:

    Henkart, Paul, 2007, SIOSEIS: Scripps Institution of Oceanography, University of California - San Diego, LaJolla, CA.

    Online Links:

    Michael W. Norris and Alan K. Faichney, 2002, SEGY Rev.1 Data Exchange Format1: Society of Exploration Geophysicists, Tulsa, OK.

    Online Links:

    Barnhardt, Walter A. , Andrews, Brian D. , and Butman, Bradford, 2006, High-Resolution Mapping of the Inner Continental Shelf: Nahant to Gloucester, Massachusetts: Open-File Report 2005-1293, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Ackerman, Seth D. , Butman, Bradford, Barnhardt, Walter A. , Danforth, William W. , and Crocker, James M. , 2006, High-Resolution Geologic Mapping of the Inner Continental Shelf: Boston Harbor and Approaches, Massachusetts: Open-File Report 2006-1008, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

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

  1. How well have the observations been checked?

    All attributes were checked in a consistent manner.

  2. How accurate are the geographic locations?

    The SB-0512i was towed approximately 10 m astern and approximately 3 m below the sea surface. RTK-GPS navigation was obtained from the receiver mounted above the interferometric sonar head, but seismic towfish layback was not accounted for. The layback of the towfish adds additional uncertainty due to changes in angle and scope of the tow cable in response to sea state and vessel speed. Based upon horizontal offsets between the fish and GPS receiver, GPS accuracies, and fish motion behind the vessel, the resulting positional accuracy is assumed to be ± 20 m.

  3. How accurate are the heights or depths?

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

    Sections of tracklines where navigation was recorded but no seismic data were logged are not included.

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

    Any spurious data points were removed during processing. For each seismic trackline there is one seismic-profile image that is hyperlinked by the field 'Image'. No duplicates exist.

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 redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the source of this information.

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

    Brian Andrews
    U.S. Geological Survey, Woods Hole Science Center
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543
    USA

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

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

    Downloadable Data

  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?

    This zip file contains data available in Environmental Systems Research Institute (ESRI) point shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.

Who wrote the metadata?

Dates:
Last modified: 18-Dec-2008
Metadata author:
Brian Andrews
U.S. Geological Survey
Geographer
384 Woods Hole Rd.
Woods Hole, MA 02543-1598
USA

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

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.25 on Thu Dec 18 10:44:14 2008