Archive of Boomer Seismic Reflection Data Collected on USGS Cruise 97KEY01, Upper and Middle Florida Keys, 12 October - 1 November, 1997.

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Frequently anticipated questions:


What does this data set describe?

Title:
Archive of Boomer Seismic Reflection Data Collected on USGS Cruise 97KEY01, Upper and Middle Florida Keys, 12 October - 1 November, 1997.
Abstract:
This report consists of two-dimensional marine seismic reflection profile data from the upper and middle Florida Keys. The area of operations extended from just north of Molasses Reef off north Key Largo (Upper Keys) to the east boundary of Looe Key National Marine Sanctuary (Lower Keys). These data were acquired in October and November of 1997 with the Charter Vessel Captain's Lady. The data are available in a variety of formats, including binary, ASCII, HTML, Shapefiles, JPG and GIF images. Binary data are in Society of Exploration Geophysicists (SEG) SEG-Y format and may be downloaded for further processing or display. Reference maps and JPG images of the profiles may be viewed with your WWW browser.
For more information on the seismic surveys see http://walrus.wr.usgs.gov/infobank/c/c197fl/html/c-1-97-fl.meta.html
These data are also available via GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean (http://www.virtualocean.org/) earth science exploration and visualization applications.
Supplemental_Information:
Seismic reflection profiles are acquired by means of an acoustic source (usually generated electronically), and a hydrophone or hydrophone array. Both elements are typically towed in the water behind a survey vessel. The sound source emits a short acoustic pulse, which propagates through the water and sediment columns. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), and detected at the hydrophone. This process is repeated at intervals ranging between 100 ms and 1s depending on the source type. In this way a two-dimensional image of the geologic structure beneath the ship track is constructed. Seismic data are stored in SEG-Y format, which is a standard digital format that can be read and manipulated by most seismic-processing software packages. The SEG-Y file format includes a 3200-byte descriptive header that contains detailed information regarding the data acquisition and processing parameters. All data presented here are stored in SEG-Y, Integer, Motorola format. The SEG-Y formatted trace data files have a .tra extension. Additional recording parameters for each seismic data file can also be found in the .par file associated with each .tra file. However, the .par files and the plg_gga.pln file are only needed to replay the data with Triton Elics Delph Seismic software. The seismic source employed here consisted of a boomer transducer towed on a sled at the sea surface providing 100 joules per shot. The reflected energy was received by an Innovative Transducer Inc. (ITI) solid core streamer and recorded by PC-based Triton-Elics Delph Seismic acquisition software. The ITI streamer contains 10 hydrophones evenly spaced over 6 meters however only data received by elements 5-8 where summed, resulting in a higher signal to noise ratio for the data. The streamer was positioned parallel to the boomer sled and laterally separated from it by 7 m. The sled was towed 20 m behind the GPS antennae. The sample frequency of the data was 12000 Hz and the total record length was 100 ms. The fire rate was every 0.25 sec, which resulted in a shot spacing of about 0.5 m based on survey speeds of 3.5-4 knots. P-Code GPS navigation was fed to the acquisition system every second by a Rockwell navigation receiver. The accuracy of this receiver is within 100 m. However, the data required some editing. A filter was designed to remove spurious data values and these edited results can be used to generate trackline maps at any scale or projection desired, however the shotpoint data has not been corrected to reflect the 20 m offset between the source and the GPS antenna. Also the raw navigation files did not have year or julian day written to the headers. This information was handwritten into the edited and shotpoint navigation files. Position fixes for every 500th shotpoint and the start and end of line are also provided as an aide for easy registering of the data after projection. The trackline maps provided in this report are geographic projections and were created using ESRI's GIS software ArcView 3.2 and exported to Adobe Illustrator for further editing, then saved as GIF images. These GIF images are viewable with your WWW browser. All navigation files are stored as flat ASCII text files. Included on this disc are GIS files created with ESRIs Arcview 3.2, displaying the shotpoint information for each seismic trackline. These files are compatible with either ArcView 3.x (UNIX or WINDOWS) or ArcGIS 8.1 (WINDOWS). The files can also be viewed using the Windows compatible public domain software ArcExplorer 2.0, and 4.0. To download a free copy of ArcExplorer go to the ESRI website (http://www.esri.com/software/arcexplorer/index.html). Field Activity Collection System (FACS) logs are available in both html and Rich Text format, along with the scanned GIF images of the original logbooks.
  1. How might this data set be cited?
    Peery, Gina M., Lidz, Barbara, and Wiese, Dana S., 2002, Archive of Boomer Seismic Reflection Data Collected on USGS Cruise 97KEY01, Upper and Middle Florida Keys, 12 October - 1 November, 1997.: U.S. Geological Survey Open-File Report 02-421, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -80.29
    East_Bounding_Coordinate: -81.39
    North_Bounding_Coordinate: 25.15
    South_Bounding_Coordinate: 24.40
  3. What does it look like?
    http://pubs.usgs.gov/of/2002/of02-421/MAPS/fullarea.gif (GIF)
    A full survey map of the tracklines collected during USGS Cruise 97KEY01, in October and November, 1997, along the upper and middle Florida Keys. This map is a geographic projection. It was created using ESRIs GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing, and saved for the web as a GIF image.
    http://pubs.usgs.gov/of/2002/of02-421/MAPS/areaA.gif (GIF)
    A survey map of the tracklines collected in Area A during USGS Cruise 97KEY01, in October and November, 1997, along the upper and middle Florida Keys. This map is a geographic projection. It was created using ESRIs GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing, and saved for the web as a GIF image.
    http://pubs.usgs.gov/of/2002/of02-421/MAPS/areaB.gif (GIF)
    A survey map of the tracklines collected in Area B during USGS Cruise 97KEY01, in October and November, 1997, along the upper and middle Florida Keys. This map is a geographic projection. It was created using ESRIs GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing, and saved for the web as a GIF image.
    http://pubs.usgs.gov/of/2002/of02-421/MAPS/areaC.gif (GIF)
    A survey map of the tracklines collected in Area C during USGS Cruise 97KEY01, in October and November, 1997, along the upper and middle Florida Keys. This map is a geographic projection. It was created using ESRIs GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing, and saved for the web as a GIF image.
    http://pubs.usgs.gov/of/2002/of02-421/MAPS/areaD.gif (GIF)
    A survey map of the tracklines collected in Area D during USGS Cruise 97KEY01, in October and November, 1997, along the upper and middle Florida Keys. This map is a geographic projection. It was created using ESRIs GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing, and saved for the web as a GIF image.
    http://pubs.usgs.gov/of/2002/of02-421/MAPS/areaE.gif (GIF)
    A survey map of the tracklines collected in Area E during USGS Cruise 97KEY01, in October and November, 1997, along the upper and middle Florida Keys. This map is a geographic projection. It was created using ESRIs GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing, and saved for the web as a GIF image.
    http://pubs.usgs.gov/of/2002/of02-421/MAPS/areaF.gif (GIF)
    A survey map of the tracklines collected in Area F during USGS Cruise 97KEY01, in October and November, 1997, along the upper and middle Florida Keys. This map is a geographic projection. It was created using ESRIs GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing, and saved for the web as a GIF image.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 12-Oct-1997
    Ending_Date: 01-Nov-1997
    Currentness_Reference:
    Data assumed to be constant over time but may change due to geologic processes.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Seismic Reflection Profile Section
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference:
      Horizontal X and Y locations (latitude and longitude) for each shot location are provided in ASCII position files, along with the time the shot was recorded in Greenwich Mean Time (GMT).
      This is a Point data set.
    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 0.000278. Longitudes are given to the nearest 0.000278. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is WGS 84.
      The ellipsoid used is WGS 1984.
      The semi-major axis of the ellipsoid used is 6378137 m.
      The flattening of the ellipsoid used is 1/298.257.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Binary data file: Each profile is available as a binary file in Society of Exploration Geophysicists SEG-Y format. A SEG-Y file consists of 1) a 3200-byte file identification record of ASCII formatted general information; 2) a 400-byte binary record with information such as sample rate and record length specific to the data set; and 3) multiple records, one seismic reflection trace per record. Each trace record is preceded by a 240-byte "trace header" containing information such as trace number and acquisition day and time specific to each trace. The trace data are represented as a time series of unitless 16-bit integer or 32-bit real numbers proportional to the reflection coefficient. The SEG-Y file is useful only if you have access to specialized software designed to process and display seismic reflection data. These SEG-Y files have a .tra extension. These .tra files range in size from the smallest being 14 MB to the largest being 142 MB.
    Entity_and_Attribute_Overview:
    Graphic image file: Each profile is available as a GIF or JPG image. The trackline maps provided are GIF images that contain hot-links to the seismic profile JPG images. The profiles range in size from 1.1 MB to 8.9 MB.
    Entity_and_Attribute_Detail_Citation:
    Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, v. 40, n. 2, p. 344 - 352. Also available online at: <http://www.seg.org/publications/tech-stand/index_body.html>

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Gina M. Peery
    • Barbara Lidz
    • Dana S. Wiese
  2. Who also contributed to the data set?
    The USGS Coastal and Marine Geology Program (CMGP) provided the funding for research east and northeast of the Looe Key National Marine Sanctuary (LKNMS), to Molasses Reef off the upper Keys. Billy Causey, Superintendent of the Florida Keys National Marine Sanctuary (FKNMS), and Sanctuary Rangers (Florida Department of Natural Resources, Bureau of Environmental Land Management) are thanked for their cooperation during the field survey. Personnel from the USGS in St. Petersburg, Fla., and the National Oceanic and Atmospheric Administrations (NOAA) FKNMS conducted most of the project in the middle and upper Keys as a cooperative study under permit FKNMS-29-97. We thank Captain Stephen R. Cawthon who led Captain's Lady on her final voyage as a research vessel in 1997, for assistance in data collection. Appreciation is extended to numerous colleagues for their field assistance. All are acknowledged by name in publications resulting from each part of the project. Stanley D. Locker, University of South Florida St. Petersburg campus, assisted in numerical data conversion to compensate for the rapid speed-of-sound return in shallow water. James G. Flocks, USGS geologist, produced the seismic-profile trackline navigation and data map panels for contouring. Digital cartographer Lance E. Thornton digitized final contours into the ARC/INFO GIS program for the bedrock and isopach plates. Jeff Dismukes provided scripts for editing and reformatting the navigation data for use with ESRIs ArcView 3.2. The authors greatly appreciate the efforts of these colleagues.
  3. To whom should users address questions about the data?
    Barbara Lidz
    U.S. Geological Survey
    Geologist
    600 Fourth Street South
    St. Petersburg, FL
    USA

    (727) 803-8747 X3031 (voice)
    blidz@usgs.gov

Why was the data set created?

Marine seismic reflection data are used to image and map sedimentary and structural features of the seafloor and subsurface. These data are useful in mapping the extent and thickness of shallow sedimentary units in the upper and middle Florida Key, and in assessing other submarine geologic characteristics and features. The main objective of this cruise was to fill a major gap in the seismic data record. Data had not been collected for this area at any time during a 20-year study of the reef track.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2001 (process 1 of 6)
    Boomer processing: Raw SEG-Y data was processed with SU and (Triton Elics Software) to produce the JPG formatted seismic profiles included in this report. A representative data processing sequence consisted of: 1)Bandpass filter: 300-500-2500-3000 Hz; 2)Automatic gain control; 3)Postscript display at 25ms/in and 300shots/in for all tracklines. 4)Convert Postscripts to GIF format, then to JPG format.
    Date: 2001 (process 2 of 6)
    Positional (navigation) data: As the seismic reflection data were acquired, the position of the vessel was continuously determined with the P-Code Global Positioning System (GPS). Positions were recorded approximately every second, and written to the SEG-Y header. The ASCII 500 shotpoint navigation files were extracted from the SEG-Y headers using SU scripts.
    Date: 2001 (process 3 of 6)
    Editing navigation: The raw navigation files were extracted from Delph Seismic V2.10, and then run through a filter to edit out the spurious fixes. The filtered data was also reformatted for use with ESRI's GIS software ArcView 3.2. The edited navigation files also had year and Julian day manually entered to each file.
    Date: 2001 (process 4 of 6)
    Open File preparation: No processing has been done to the SEG-Y data files provided on this DVD. The data were displayed as 8-bit gray scale Postscript files using the Seismic Unix 'psimage' algorithm. The Postscript images were then converted to GIF images with Aladdin Ghostscript. Then converted to JPG with Image Magick. Only the JPG images are presented here.
    Date: 24-Jan-2017 (process 5 of 6)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 13-Oct-2020 (process 6 of 6)
    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?

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

  1. How well have the observations been checked?
    The validity or accuracy of marine seismic reflection profiles is highly qualitative, and depends on equipment and operating condition variables. After visual inspection of the JPG images provided in this report these notes must be made about the data. Important Notes: 1.Seismic Profiles key9717b, key9717c, key9717d, key9718a, key9718b, key9723a and key9728a contain deep water delays ranging from 10 ms to 40 ms. 2.Also small 0.5 ms to 2 ms static shifts are seen in all profiles. These shifts vary for each profile and last for short irregular periods of time. 3.Only 70 ms of data was collected for trackline key9717c; all other lines were collected with 100 ms of data saved. 4.Trackline key9716t contains no usable data; it was a test line.
  2. How accurate are the geographic locations?
    The position accuracy was determined with the Rockwell PLGR P-code GPS receiver fed to the acquistion software, FUGAWI V2.08. The accuracy of this receiver is within 100 m.
  3. How accurate are the heights or depths?
    The vertical position was local sea level and there have been no corrections to a vertical datum or for tidal variations.
  4. Where are the gaps in the data? What is missing?
    These data are collected along tracklines (2D). Therefore, data are inherently incomplete. Geologic details between lines must be inferred. All tracklines were recorded to 100ms.
  5. How consistent are the relationships among the observations, including topology?
    This data set is from a single cruise with consistant instrument calibrations.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. These data are held in the public domain.
Use_Constraints:
The U.S. Geological Survey requests to be acknowledged as the originator of the data in future products or derivative research.
  1. Who distributes the data set? (Distributor 1 of 1)
    Rob Wertz
    U.S. Geological Survey
    Manager - Data Management Group
    600 Fourth Street South
    St. Petersburg, FL
    USA

    (727) 803-8747 X3045 (voice)
    rwertz@usgs.gov
    Contact_Instructions:
    Data may be available on-line only by special arrangement with the distributor above.
  2. What's the catalog number I need to order this data set? U.S. Geological Survey Open-File Report 02-XXX DVD
  3. What legal disclaimers am I supposed to read?
    This Digital Versatile Disc (DVD) publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this DVD have been used bythe USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: The SEG-Y standard format (Barry and others, 1975) consists of the following: a 3600-byte reel identification header with the first 3200 bytes consisting of an ASCII header block and a 400-byte binary header block. Both headers include information specific to line and reel number. The trace data block follows the reel identification header. The first 240 bytes of each trace block is the binary trace identification header. The seismic data samples follow the trace identification header. in format SEG-Y
      Media you can order: DVD (format UDF (Universal Disc Format))
      Note: UNIX, LINUX, DOS, MAC
      Data format: SEGY data download
      Network links: http://cmgds.marine.usgs.gov/data/97key01/boomer/
    • Cost to order the data:

      available from the Denver Open-File Sales department, prices vary.

    • Special instructions:
      Most open-file reports are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225 (telephone: 303-202-4210; email: infoservices@usgs.gov)
  5. What hardware or software do I need in order to use the data set?
    Use of SEG-Y data requires specialized seismic processing software, such as Unix or Linux based public domain software Seismic Unix (SU) developed by the Colorado School of Mines, Center for Wave Phenomena, which can be downloaded from <http://www.cwp.mines.edu/cwpcodes> free of charge.

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
Gina M. Peery
U.S. Geological Survey
Geologist - Data Management Group
600 Fourth Street South
St. Petersburg, FL
USA

(727) 803-8747 X3120 (voice)
gpeery@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/of2002-421metadata.faq.html>
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