PNG formatted images for multi-channel streamer seismic-reflection profiles collected in 2015 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA

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Frequently anticipated questions:

What does this data set describe?

Title:
PNG formatted images for multi-channel streamer seismic-reflection profiles collected in 2015 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA
Abstract:
The Delmarva Peninsula is a 220-kilometer-long headland, spit, and barrier island complex that was significantly affected by Hurricane Sandy in the fall of 2012. The U.S. Geological Survey conducted cruises during the summers of 2014 and 2015 to map the inner continental shelf of the Delmarva Peninsula using geophysical and sampling techniques to define the geologic framework that governs coastal system evolution at storm-event and longer timescales. Geophysical data collected during the cruises include swath bathymetric, sidescan sonar, chirp and boomer seismic reflection profiles, grab sample and bottom photograph data. More information about the USGS survey conducted as part of the Hurricane Sandy Response-- Geologic Framework and Coastal Vulnerability Study can be found at the project website or on the WHCMSC Field Activity Web pages: https://woodshole.er.usgs.gov/project-pages/delmarva/, https://cmgds.marine.usgs.gov/fan_info.php?fan=2014-002-FA and https://cmgds.marine.usgs.gov/fan_info.php?fan=2015-001-FA. Data collected during the 2014 survey can be obtained here: https://doi.org/10.5066/F7MW2F60
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, PNG formatted images for multi-channel streamer seismic-reflection profiles collected in 2015 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA: data release DOI:10.5066/F7P55KK3, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Sweeney, Edward M., Pendleton, Elizabeth A., Ackerman, Seth D., Andrews, Brian D., Baldwin, Wayne E., Danforth, William W., Foster, David S., Thieler, E. Robert, and Brothers, Laura L., 2016, High-resolution geophysical data collected along the Delmarva Peninsula 2015, U.S. Geological Survey Field Activity 2015-001-FA: data release DOI:10.5066/F7P55KK3, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.831103
    East_Bounding_Coordinate: -75.156956
    North_Bounding_Coordinate: 37.606200
    South_Bounding_Coordinate: 37.001644
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2015-001-FA/data/seismics/MCS-images/2015-001-FA_MCS_images_browse.jpg (JPEG)
    Thumbnail image of multi-channel reflection point profile image for Delmarva Peninsula.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 10-Jun-2015
    Ending_Date: 17-Jun-2015
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions, type Pixel
    2. What coordinate system is used to represent geographic features?
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    The PNG images can be hyperlinked to their shapefile location in ArcGIS. The images show two-way travel time (seconds) on the y-axis and distance along profile (in 500 reflection point intervals) on the x-axis.
    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?
    Edward M. Sweeney
    U.S. Geological Survey
    Physical Scientist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2256 (voice)
    508-457-2310 (FAX)
    emsweeney@usgs.gov

Why was the data set created?

PNG images of each seismic profile were generated in order to incorporate images of the seismic profiles into Geographic Information System (GIS) projects. These images represent approximately 1,460 km of multi-channel streamer seismic-reflection data collected by the U.S. Geological Survey during cruise 2015-001-FA along the Delmarva Peninsula, MD and VA. Each profile image can be hotlinked to its corresponding trackline navigation contained within the Esri polyline shapefile '2015-001-FA_MCS_tracklines.shp'. Even 100 reflection point tic marks (with labels every 500 reflection points) along the top of the PNG images correlate to the positions of 100-rp intervals within the Esri point shapefile '2015-001-FA_MCS_100rp.shp'.

How was the data set created?

  1. From what previous works were the data drawn?
    MCS data (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, Raw MCS data.

    Type_of_Source_Media: disc
    Source_Contribution:
    MCS seismic data were collected using S-Boom source and a 100-m long GeoEel 16-channel streamer. The applied acoustics S-Boom source was towed astern of the M/V Scarlet Isabella at a power level of 400 joules. The Geometrics GeoEel, 16-channel liquid filled digital streamer was towed from the starboard side of the vessel, and the center of the first channel of the active section was 10 to 20 meters aft of the boomer source. The streamer had a group interval of 3.25 meters connected to Geometrics Streamer Power Supply Unit (SPSU). Data were acquired in Geometrics SEG-D format on Windows PC controller system using Geometrics CNT-1 software. The fire rate was 1 s, the record length was 250 ms and the sample interval was 0.25 ms.
  2. How were the data generated, processed, and modified?
    Date: 14-Jul-2015 (process 1 of 4)
    A SIOSEIS seismic processing software script (sio_geom) was used as follows:
    1. The raw SEG-D shot files were read with the process SEGDDIN specifying the geometrics format; the process HEADER was used to insert time of day into the header based on the start and end times recorded in HYPACK files and from the cruise survey log entries. The process GEOM was used to describe the shot and streamer geometries and to calculate the reflection point (RP) numbers used to gather (sort traces) the seismic line. The process GEOM also set the shot-receiver distance in the trace header of every trace. GEOM type 9 was used for all lines (except for lines 2 to 6 and l30f1) to calculate distances between shots from shot point locations in the SEG-D headers and to bin traces as common RP's (reflection points). GEOM type 6 was specified for lines 2 to 6 (because positions were absent or bad in the header), which computes a distance from last shot (DFLS) for each shot based on the shot time in the header and the navigation from an ASCII file containing time and position. The ASCII navigation file was derived from the HYPACK data and merged with RP files with the Unix join command. The process GATHER was used to sort the shot order traces by the RP numbers (computed by GEOM). A normal move out (NMO) applied a travel time correction to each trace based on time offset and a velocity of 1530 m/s. Lastly, the shot ordered trace gathers were written with the process DISKOX in SEG-Y rev. 1, IEEE floating point format. This step and all subsequent steps were completed by Dave Foster.
    2. A SIOSEIS script (sio_gather) was used to sort traces into RP order trace gathers using the RP values calculated by the SIOSEIS process GEOM. RP ordered navigation coordinates to be used in process step 3.
    3. A SIOSEIS script (sio_nmo) was used to apply a normal moveout to the RP gathers from step 2. Moveout velocities of 1510 to 1540 m/s were used.
    4. A shell script (layback_stack) read the navigation output created in step 2 and extracted the navigation coordinates for channel 1 within each RP. The result was read by a Python script (layback_rp.py) which applied a layback correction (offset from the GPS antenna source and to the midpoint from the source to the first active channel). The script calculated easting and northing differential values between trace positions. Headings between consecutive traces were calculated using the arctangent function (arctan2(dy,dx)), and reciprocal back bearings were determined using a lookup table. Back bearings were smoothed along track using a moving median function. Layback easting and northing offsets were calculated by multiplying the layback distance by the sine and cosine of the smoothed back bearing, respectively. Offset values were then added to the original coordinates to produce layback positions. The script (layback_stack) then called a SIOSEIS script (siostackpop) which stacked the RP gathers and apply a bandpass filter. The process DISKIN read the RP sorted SEG-Y file. The process STACK was used to sum traces, compute the average amplitude for each trace sample, and write the computed samples to one trace. The trace header values of the first trace in the gather were used for the stacked trace. The process FILTER applied a zero-phase bandpass frequency domain filter between 350 and 1800 Hz with a slope of 48 decibel per octave slope. The process HEADER was used to populate the SEG-Y headers with the layback corrected RP coordinates. Lastly, the processed stacked traces were written to disk with the process DISKOX in SEG-Y rev. 1 , IEEE floating point format. The script layback_stack used AWK to format navigation files with unique RP positions and positions for every 100 reflection points in CSV format, which contains attributes for layback corrected UTM Zone 18 coordinates, layback corrected geographic coordinates, line (file) name, year, day, RP number, and fold. Finally, a Python script (GBrptoSQL15001.py) written by Wayne Baldwin, imported the CSV files to the Spatialite (version 3.0.1) enabled SQLite (version 3.7.9) database. Esri shape polyline and shot point files were exported directly from the SQLite database.
    5. A Seismic Unix (version 4.0) script (plot_geomet) was used to read the stacked, and filtered SEG-Y files and to plot the data as 8-bit gray scale Postscript files using the Seismic Unix 'psimage' algorithm. All images were created with a horizontal scale of 60 traces per inch. Images were plotted within a constant 14-inch vertical window (Two-Way Travel Time) duration. The Postscript images were then converted with ImageMagick (version 6.8.7-2) to PNG format. Person who carried out this activity:
    Dave Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2271 (voice)
    (508) 457-2310 (FAX)
    dfoster@usgs.gov
    Date: 19-Apr-2017 (process 2 of 4)
    The online links to the data were updated to reflect the new server hosting the data. Additionally, other small edits could be made to the metadata, such as modifying http to https where appropriate. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 3 of 4)
    USGS Thesaurus keywords added to the keyword section. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 4 of 4)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Pendleton, Elizabeth A., Ackerman, Seth D., Baldwin, Wayne E., Danforth, William W., Foster, David S., Thieler, E. Robert, and Brothers, Laura L., 2015, High-resolution geophysical data collected along the Delmarva Peninsula 2014, U.S. Geological Survey Field Activity 2014-002-FA: data release DOI:10.5066/F7MW2F60, U.S. Geological Survey, Reston, VA.

    Online Links:

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?
    Differential Global Positioning System (DGPS) and Wide Area Augmentation System (WAAS) GPS navigation data were acquired with a Proflex receiver and a Hemisphere receiver, which were both recorded using HYPACK software (version 14.0.9.47) (www.hypack.com). The DGPS antenna was located on the port-side of the acquisition van. DGPS horizontal positional accuracy is estimated to be within 3-5 m; WAAS enable GPS is estimated to be less than 2 m. The applied acoustics S-Boom source was towed 20-m (lines 1-14) and 25-m (lines 15-39) astern of the M/V Scarlet Isabella. The 100-m long GeoEel 16-channel streamer was towed from the starboard side of the M/V Scarlett Isabella on a 4.82 m boom with 20 m (lines 1-18f1, 37 and 38) and 15 m (lines 18f2-36, 39) of tow cable and 10 m of isolation in front of the start of the active channel. The Geometrics CNT-1 seismic acquisition software (version 5.361) logged the navigation coordinates (in arc seconds) to individual trace headers using the Proflex receiver (JD 161-162) and the Hemisphere receiver (JD 162-168). Layback distance between the GPS antenna and the source and receiver were calculated in post processing. Although horizontal accuracy of navigation positioning is assumed to be within 2 m, inaccuracies likely exceed this value in the seismic reflection data due to uncertainty of azimuths calculated in the layback correction (described in the processing steps).
  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 such as some turns and transits. There is no line l6f1.
  5. How consistent are the relationships among the observations, including topology?
    Processed seismic data were converted to PNG format for ease of seismic trace display. Quality control was conducted during processing.

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 originator of the dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    Edward M. Sweeney
    U.S. Geological Survey
    Physical Scientist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2256 (voice)
    508-457-2310 (FAX)
    emsweeney@usgs.gov
  2. What's the catalog number I need to order this data set? USGS data release 2015-001-FA MCS data from the Delmarva Peninsula area (2015-001-FA_MCS_images.zip). The zip file contains a folder with 61 PNG images named according to line and file number convention with an _stack appended to note processing. A browse graphic (2015-001-FA_MCS_images_browse.jpg) and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata files (2015-001-FA_MCS_images.xml) in four standard formats are also included in the zip file.
  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?
    These data can be viewed with any PNG image viewing software. The zip files must be uncompressed in order to view the images.

Who wrote the metadata?

Dates:
Last modified: 19-Nov-2021
Metadata author:
Edward M. Sweeney
U.S. Geological Survey
Physical Scientist
384 Woods Hole Road
Woods Hole, Massachusetts
USA

508-548-8700 x2256 (voice)
508-457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS or the email is otherwise invalid.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/field_activities/2015_001_fa/2015-001-FA_MCS_images.faq.html>
Generated by mp version 2.9.50 on Fri Nov 19 13:02:55 2021