PNG formatted images of EdgeTech SB-512i chirp seismic-reflection data 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 of EdgeTech SB-512i chirp seismic-reflection data 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 of EdgeTech SB-512i chirp seismic-reflection data 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: -75.891075
    East_Bounding_Coordinate: -75.156914
    North_Bounding_Coordinate: 37.839169
    South_Bounding_Coordinate: 36.999886
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2015-001-FA/data/seismics/512i-images/2015-001-FA_512i_images_browse.jpg (JPEG)
    Thumbnail image of chirp seismic-reflection profile image for Delmarva Peninsula.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 10-Jun-2015
    Ending_Date: 14-Jul-2015
    Currentness_Reference:
    ground condition; data were not collected on 20150628 (transition between Legs 1 and 2 of the survey)
  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 shot 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 data represent approximately 5,500 km of chirp 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_512i_tracks.shp'. Shotpoint index markers along the top of the PNG images correlate to the positions of 500 shot intervals within the Esri point shapefile '2015-001-FA_512i_500sht.shp'.

How was the data set created?

  1. From what previous works were the data drawn?
    SEG-Y and JSF 512i data (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, 512i PNG image data.

    Type_of_Source_Media: disc
    Source_Contribution:
    Chirp seismic data were collected using an EdgeTech Geo-Star FSSB sub-bottom profiling system and an SB-0512i towfish (0.5-12 kHz), which was mounted on a catamaran and towed astern of the M/V Scarlett Isabella of Cape May, NJ. Chesapeake Technology's SonarWiz (versions 5.00.0015 and 5.06.0058) seismic acquisition software was used to control the Geo-Star topside unit, digitally log trace data in the SEG-Y Rev. 1 format (IEEE floating point) and JSF format, and record GPS navigation coordinates to the SEG-Y trace headers (in arc seconds of Latitude and Longitude, multiplied by a scalar of 100). Data were acquired using a 250 ms shot rate, a 5-ms pulse length, and a 0.5 to 8 kHz frequency sweep. Recorded trace lengths were approximately 180 ms.
  2. How were the data generated, processed, and modified?
    Date: 14-Jul-2015 (process 1 of 4)
    Scripts within SIOSEIS (version 2013.1.1) and Seismic Unix (version 4.2) were used to process SEG-Y data, create navigation files, and plot images. The processing flow and scripts used to produce swell-filtered PNG images are summarized below:
    1. SIOSEIS (version 2013.1.1) was used to read SEG-Y files, renumber shots starting from one, extract the envelope-detected trace, and write out new SEG-Y files. The original shot numbers, which were assigned by SonarWiz sequentially over the duration of an acquisition session despite SEG-Y file changes, are preserved in the raw SEG-Y data.
    2. The SIOSEIS script Sio_medianstk was used to minimize S-boom cross talk (when multi-channel streamer lines were recorded simultaneously: Julian day 161-168) with a two-trace median stack (trim 50 percent of the values furthest from the median amplitude) and improve water bottom picking. This script was used for all lines even after multi-channel streamer was turned off, due to the improvements made to water bottom picks.
    3. The script Read512i_mstk was used to read median filtered stacked and renumbered 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, 500, and shots with unique navigation coordinates. Geographic coordinates (WGS 84) were converted to UTM zone 18 N coordinates (WGS 84) using Proj (version 4.6.0). End shots and shots at multiples of 100 may not have unique navigation coordinates. Separate text files containing the first and last shots and even 500 shot intervals were also saved. A 500 shot interval was chosen because it corresponds to the annotation interval provided along the top of the seismic-reflection profile images. Read512i_mstk called a Python script 512itoSQL15001.py, written by Wayne Baldwin, which imported the CSV files to the Spatialite (version 3.0.1) enabled SQLite (version 3.7.9) database.
    4. The SIOSEIS script siothresh_pltwbt was used to pick the water-bottom time from the median stacked SEG-Y files, apply a swell filter to smooth water-bottom time picks and shift the trace data by the difference between the smoothed and unsmoothed water bottom time before writing the shifted trace data to a new SEG-Y file.
    5. The Seismic Unix script Plot512i_s creates a swell-filtered PNG image using ImageMagick (version 6.6.1) of each seismic line that is 12 inches high. Images show two-way travel time (seconds) along the y-axis (left margin) and distance along profile (in 10,000 shot intervals) on the x-axis (along top of profile). 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: 20-Apr-2017 (process 2 of 4)
    The online links to the data were updated to reflect the new server hosting the data. The original release had 3 download files (2015-001-FA_512i_images1of3.zip, 2015-001-FA_512i_images2of3.zip, 2015-001-FA_512i_images3of3.zip) with each file approximate 3.5 GB in size. In order to facilitate downloads, the data were broken into smaller zip files. A total of 11 zip files were created with each file approximately 1 GB insize. Each file contains a portion of the seismic-reflectino profile images, the browse graphic, and the CSDGM metadata.
    The breakdown of the seismic-refleciton profiles is as follows:
    2015-001-FA_512i_images1of11.zip contains lines 1-25
    2015-001-FA_512i_images2of11.zip contains lines 26-34
    2015-001-FA_512i_images3of11.zip contains lines 35-42
    2015-001-FA_512i_images4of11.zip contains lines 43-59
    2015-001-FA_512i_images5of11.zip contains lines 60-74
    2015-001-FA_512i_images6of11.zip contains lines 75-94
    2015-001-FA_512i_images7of11.zip contains lines 95-102
    2015-001-FA_512i_images8of11.zip contains lines 103-129
    2015-001-FA_512i_images9of11.zip contains lines 130-149
    2015-001-FA_512i_images10of11.zip contains lines 150-159
    2015-001-FA_512i_images11of11.zip contains lines 160-178 and turn1.
    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?
    Although navigation is not stored in the images, positional accuracy is relevant to the accuracy of these data. The EdgeTech SB-0512i subbottom profiler was mounted on a catamaran sled and towed at the sea surface approximately 43 m astern of the M/V Scarlett Isabella. The transducer depth below water line was 0.5 meters below catamaran floats. Navigation data for the 512i were collected using a Differential GPS (DGPS) and Wide Area Augmentation System (WAAS) GPS enabled Garmin receiver, which was located on the catamaran sled and connected to the acquisition computer via a serial cable. Positioning data were recorded in SonarWiz (versions 5.00.015 and 5.06.0058) acquisition software, which logged positioning coordinates to individual trace headers SEG-Y and JSF format. Horizontal positional accuracy is assumed to be within 2 m at the GPS receiver; however, horizontal position uncertainty increases with sonar and sled motion, which was not compensated for at the sonar transducer.
  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 a single image for every trackline. There is no line l155f1.
  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 512i PNG imagery from the Delmarva Peninsula area (2015-001-FA_512i_images1of11.zip, 2015-001-FA_512i_images2of11.zip, 2015-001-FA_512i_images3of11.zip, 2015-001-FA_512i_images4of11.zip, 2015-001-FA_512i_images5of11.zip, 2015-001-FA_512i_images6of11.zip, 2015-001-FA_512i_images7of11.zip, 2015-001-FA_512i_images8of11.zip, 2015-001-FA_512i_images9of11.zip, 2015-001-FA_512i_images10of11.zip, and 2015-001-FA_512i_images2of11.zip). The 11 zip files contain a total of 372 PNG images named according to line and file number convention with an '_s' appended to note swell-filter processing. A browse graphic (2015-001-FA_512i_images_browse.jpg) and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata files (2015-001-FA_512i_images.xml) in four standard formats are also included in each 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_512i_images.faq.html>
Generated by mp version 2.9.50 on Fri Nov 19 13:02:55 2021