PNG images of each chirp seismic profile collected south of Martha's Vineyard and north of Nantucket by the U.S. Geological Survey during field activity 2013-003-FA offshore of Massachusetts in 2013

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Frequently anticipated questions:


What does this data set describe?

Title:
PNG images of each chirp seismic profile collected south of Martha's Vineyard and north of Nantucket by the U.S. Geological Survey during field activity 2013-003-FA offshore of Massachusetts in 2013
Abstract:
These data were collected under a cooperative agreement between the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center (WHCMSC). 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 resources, and assessing environmental changes due to natural or human impacts. The project is focused on the inshore waters of coastal Massachusetts, primarily in water depths of 5 to 30 meters (m) deep. 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/). The geophysical data were collected during a survey in 2013 during USGS Field Activity 2013-003-FA (http://cmgds.marine.usgs.gov/fan_info.php?fa=2013-003-FA) and cover approximately 185 square kilometers of the inner continental shelf.
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, PNG images of each chirp seismic profile collected south of Martha's Vineyard and north of Nantucket by the U.S. Geological Survey during field activity 2013-003-FA offshore of Massachusetts in 2013: Open-File Report 2016-1168, 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.

    Ackerman, Seth D., Brothers, Laura L., Foster, David S., Andrews, Brian D., Baldwin, Wayne E., and Schwab, William C., 2016, High-Resolution Geophysical Data from the Inner Continental Shelf: south of Martha's Vineyard and north of Nantucket, Massachusetts: Open-File Report 2016-1168, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.805299
    East_Bounding_Coordinate: -70.034089
    North_Bounding_Coordinate: 41.389034
    South_Bounding_Coordinate: 41.195712
  3. What does it look like?
    http://pubs.usgs.gov/of/2016/1168/GIS_catalog/browse_img/big/2013-003-FA_l196f1_s.jpg (JPEG)
    Sample image of a PNG chirp seismic-reflection profile image
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 22-May-2013
    Ending_Date: 11-Jun-2013
    Currentness_Reference:
    ground condition of survey dates: 20130522-20130611; see Completeness_Report for more information
  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?
    2013-003-FA_512i_images
    PNG images of chirp seismic reflection profiles (Source: U.S. Geological Survey)
    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 top x-axis. For longer profiles, these values are in scientific notation (i.e. 10 to the 4th power).
    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?
    David Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2271 (voice)
    508-457-2310 (FAX)
    dfoster@usgs.gov

Why was the data set created?

PNG images of each chirp seismic profile were generated to integrate the seismic profiles into Geographic Information System (GIS) projects. The PNG images represent approximately 1920 km of EdgeTech SB-512i chirp seismic-reflection profiles collected south of Marthas Vineyard and north of Nantucket, Massachusetts. Each profile image can be hotlinked to its corresponding trackline navigation contained within the Esri polyline shapefile '2013-003-FA_512i_shottrack.shp'. Even 500 shot index markers along the top of the PNG images correlate to the positions of 500 shot intervals within the Esri point shapefile '2013-003-FA_512i_shot500.shp'.The trackline and shotpoint shapefiles can be found online at http://pubs.usgs.gov/of/2016/1168/ofr2016-1168-data_catalog.html

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, raw seismic data.

    Type_of_Source_Media: disc
    Source_Contribution:
    Seismic-reflection data acquisition 2013-003-FA: 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 Technologies' SonarWiz (v.5.03.0016) 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 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 0.25-s shot rate, a 5-ms pulse length, and a 0.5 to 8 kHz frequency sweep. Recorded trace lengths were approximately 100 ms (2170 samples/trace and .000046-s sample interval).
  2. How were the data generated, processed, and modified?
    Date: 2013 (process 1 of 7)
    SIOSEIS (version 2013.2.25) was used to read SEG-Y files, renumber shots starting from one, 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. In the same process, channel one (trace one, which is the envelope detected trace) within each shot was output. Channels two and three (raw data) were discarded. Person who carried out this activity:
    Wayne Baldwin
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd
    Woods Hole, MA
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Data sources used in this process:
    • SEG-Y and JSF 512i data
    Date: 2014 (process 2 of 7)
    SIOSEIS (version 2013.2.25) was used to predict the vertical location of the sea floor for the SB-512i seismic traces by identifying the first downtrace instance of an amplitude that exceeded a user defined threshold value. Two-way travel times to the sea floor at each trace were recorded to ASCII text files. These ASCII files were imported as horizons into Kingdom Suite software where incorrect seafloor picks were edited and exported to an edited ASCII file. This process step and all subsequent process steps were performed by the same person - David Foster. Person who carried out this activity:
    David Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd
    Woods Hole, MA
    USA

    508-548-8700 x2271 (voice)
    508-457-2310 (FAX)
    dfoster@usgs.gov
    Date: 2014 (process 3 of 7)
    SIOSEIS was used to insert Kingdom Suite corrected seafloor values into the SEG-Y trace headers, minimize the effect of sea surface heave using process "swell', mute water column data using the corrected seafloor values, apply time varying gain to trace data below the seafloor (a(i) = a(i) * (t-wbt) ** alpha, for t >= wbt; alpha= 1.15 and write out new muted, gained, SEG-Y files for creation of browse images and digital interpretation.
    Date: 2014 (process 4 of 7)
    Seismic Unix (version 4.2) was used to read all processed SEG-Y files and 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 150 traces per inch. The profiles contain 80 milliseconds of Two-Way Travel Time within an 14-inch vertical window, yielding approximately 5.7 milliseconds per inch. Postscript images were converted to PNG format using ImageMagick (version 6.6.1). 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).
    Date: 20-Jul-2018 (process 5 of 7)
    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: 18-Nov-2019 (process 6 of 7)
    Crossref DOI link was added as the first link in the metadata. 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 7 of 7)
    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?
    Cohen, Jack, and Stockwell, John, 2011, CWP/SU: Seismic Un*x Release No. 4.2: Center for Wave Phenomena - Colorado School of Mines, Golden, CO.

    Online Links:

    Henkart, Paul, 2011, SIOSEIS: Scripps Institution of Oceanography, University of California - San Diego, LaJolla, CA.

    Online Links:

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

    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?
    Field activity 2013-003-FA: Although navigation is not stored in the images, positional accuracy is relevant to the accuracy of these data. The SB-0512i was mounted on a catamaran sled and towed at the sea surface approximately 30 - 40 m astern of the M/V Scarlett Isabella. Position data were provided by a Global Positioning System (GPS) navigation receiver mounted on the catamaran, and data were transmitted to the acquisition computer on the vessel via a 2.4 GHz radio link. Technical difficulties during portions of 2013-003-FA caused the GPS system mounted on the catamaran to malfunction, so DGPS navigation was obtained from a receiver mounted on top of the acquisition van. Layback positions, which account for the linear distance between the shipboard DGPS receiver and the towed catamaran vehicle, were calculated trigonometrically during post-processing. Positional accuracy is assumed to be +/- 20 m; increased uncertainty arises because layback calculations do not account for fish motion behind the vessel, which is caused by sea state and vessel speed induced changes in the angle and scope of the tow cable.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    There is a single image for every trackline. There is no line L47f1 (acquisition system froze 2 minutes into this line, no good data were recorded), there is also no line L132 and L133. Time gaps occurred during this field activity where no surveying was done due to bad weather, rough seas and stops in port for crew changes. Planned surveying was paused and no main survey line data were collected during these times:
    JD143 15:20 - JD146 20:06 (no data were collected on JD144 or JD145)
    JD149 15:40 - JD151 18:59 (no data were collected on JD150)
    JD153 00:01 - JD153 14:32
    JD155 18:16 - JD156 02:06
    JD158 06:12 - JD160 19:15 (no data were collected on JD159)
    
  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. The filenames for the PNG images are generally in the format l###f@_s.png where ### is the name of the trackline along which seismic data was collected, @ is the file iteration (indicates the survey line was split into multiple files during acquisition) and the _s indicates that this image has been "swell filtered". For example: survey line 179 was interrupted 30 minutes into the line, the ship circled around to the location where surveying was paused; there are 2 tracklines and seismic images for line 179 "l179f1_s.png" and "l179f2_s.png"

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)
    Seth Ackerman
    U.S. Geological Survey, Woods Hole Science Center
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    sackerman@usgs.gov
  2. What's the catalog number I need to order this data set? USGS data release 2013-003-FA seismic profile images in PNG format from south of Martha's Vineyard and north of Nantucket. The zip file contains 272 PNG images and metadata files in three standard formats.
  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 PNG images. The zip file also contains associated metadata. The user must have software capable of uncompressing the zip file and displaying the PNG images.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
David Foster
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 x2271 (voice)
508-457-2310 (FAX)
dfoster@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr2016-1168/2013-003-FA_512i_images_meta.faq.html>
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