Archive of Digital Boomer Seismic Reflection Data Collected During USGS Field Activity 96LCA04 in Lakes Mabel and Starr, Central Florida, August 1996

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Frequently anticipated questions:


What does this data set describe?

Title:
Archive of Digital Boomer Seismic Reflection Data Collected During USGS Field Activity 96LCA04 in Lakes Mabel and Starr, Central Florida, August 1996
Abstract:
In August of 1996, the U.S. Geological Survey conducted geophysical surveys in Lakes Mabel and Starr, Florida. This report serves as an archive of unprocessed digital boomer seismic reflection data, trackline maps, navigation files, GIS information, cruise log, and formal FGDC metadata. For detailed information about the hydrologic setting of Lake Starr and the interpretation of some of these seismic reflection data, see Swancar and others (2000) at http://fl.water.usgs.gov/publications/Abstracts/wri00_4030_swancar.html. Filtered and gained digital images of the seismic profiles are also provided. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU). Example SU processing scripts and USGS software for viewing the SEG-Y files (Zihlman, 1992) are also provided.
For more information on the seismic surveys see http://walrus.wr.usgs.gov/infobank/b/b496fl/html/b-4-96-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:
The USGS Florida Integrated Science Center (FISC) - St. Petersburg assigns a unique identifier to each cruise or field activity. For example, 96LCA04 tells us the data were collected in 1996 for the Lakes and Coastal Aquifers (LCA) project and the data were collected during the fourth field activity for that project in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the cruise ID. The naming convention used for each seismic line is as follows: xxmyy_#a, where xx is an abbreviation of the discipline the data were collected for and myy is the month and year the trackline was collected, # is a number representing a specific track, and a is a letter representing the section of a line if recording was prematurely terminated or rerun for quality or acquisition problems.The boomer plate is an acoustic energy source that consists of capacitors charged to a high voltage and discharged through a transducer in the water. The transducer is towed on a sled floating on the water surface and when discharged emits a short acoustic pulse, or shot, that propagates through the water and sediment column. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the lake bottom), detected by the receiver (hydrophone streamer), and recorded by a PC-based seismic acquisition system. This process is repeated at timed intervals (for example, 0.5 s) and recorded for specific intervals of time (for example, 100 ms). In this way, a 2-D vertical image of the shallow geologic structure beneath the ship track is produced.An ORE GeoPulse power supply provided 105 Joules per shot. Reflected energy was received by an Innovative Transducers, Inc. (ITI) ST-5 streamer and recorded by Delph Seismic acquisition software. The streamer contains 10 hydrophones evenly spaced every 0.610 m. For all lines, phones 5 - 8 were used. The streamer was directly behind the research vessel positioned parallel to the boomer sled and laterally separated from it by about 4 m. Refer to figure 1 included with this archive for a diagram of the acquisition geometry. The sample frequency of the data was 16 kHz, and record length was 100 ms. The shot spacing was highly variable, however, based on survey speeds of 2 knots and a shot rate of every 0.5 s, shot spacing was about 0.514 m.The unprocessed seismic data are stored in SEG-Y, integer, Motorola format, which is a standard digital format that can be read and manipulated by most seismic processing software packages (Barry and others, 1975). The SEG-Y formatted trace files have a .tra extension. Additional recording parameters for each trace file can also be found in the .par file associated with each .tra file. However, the .par files included here are only needed to process or display the data with Delph Seismic software. Also provided are example Seismic Unix scripts that allow the user to strip off navigation fixes from the SEG-Y headers, along with a fix for every 500 shots, and produce a filtered and gained GIF image of each profile. NOTE: Navigation data were recorded to 2 different sections of the SEG-Y trace headers, creating 2 navigation data sets. For details, see the Horizontal Positional Accuracy Report under the Data Quality Information section below.The printable profiles provided here are GIF images that were filtered and gained using Seismic Unix software. The processed SEG-Y data were exported to Chesapeake Technology, Inc. (CTI) SonarWeb software to produce interactive versions of the profiles that allow the user to obtain a geographic location and depth from the profile for a cursor position. This information is displayed in the status bar of the browser. NOTE: The only supported Web browsers that properly display all features of the interactive profiles are Internet Explorer 6 or greater for Windows and Firefox 1.5 or greater for all platforms. For all browsers, the status bar and JavaScript must be enabled. Firefox also requires "Change status bar text" to be checked under Advanced JavaScript Settings. Use of other browsers may result in spurious or no information given in the status window. Firefox may be downloaded at http://www.mozilla.com/en-US/firefox/.
  1. How might this data set be cited?
    Harrison, Arnell S., Dadisman, Shawn V., Swancar, Amy, Tihansky, Ann B., Flocks, James G., and Wiese, Dana S., 2008, Archive of Digital Boomer Seismic Reflection Data Collected During USGS Field Activity 96LCA04 in Lakes Mabel and Starr, Central Florida, August 1996: U.S. Geological Survey Data Series 346, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -81.592886
    East_Bounding_Coordinate: -81.583153
    North_Bounding_Coordinate: 27.973098
    South_Bounding_Coordinate: 27.953200
  3. What does it look like?
    http://pubs.usgs.gov/ds/346/maps/cruisenav/96lca04_location.jpg (JPEG)
    Location map of digital boomer seismic reflection data collected during USGS Field Activity 96LCA04. This map was created at a scale of 1:64,000. Refer to the Lineage section below for the trackline map creation process.
    http://pubs.usgs.gov/ds/346/maps/cruisenav/96lca04_mabel.jpg (JPEG)
    Trackline map of digital boomer seismic reflection data collected in Lake Mabel (refer to Lake Mabel on the location map) during USGS Field Activity 96LCA04. This map was created at a scale of 1:5,900.
    http://pubs.usgs.gov/ds/346/maps/cruisenav/96lca04_starr.jpg (JPEG)
    Trackline map of digital boomer seismic reflection data collected in Lake Starr (refer to Lake Starr on the location map) during USGS Field Activity 96LCA04. This map was created at a scale of 1:6,145.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 06-Aug-1996
    Ending_Date: 07-Aug-1996
    Currentness_Reference:
    Data collection interval
  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 and Zone 17 UTM coordinates) for each shot are provided as ASCII text files, along with the date and time (UTC) the shot was recorded.
      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 0.0000027. Longitudes are given to the nearest 0.0000027. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is WGS84.
      The ellipsoid used is WGS84.
      The semi-major axis of the ellipsoid used is 6378137.00.
      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: Trace data are available as binary files in SEG-Y format. These files have a .tra extension and range in size from 40 to 83 MB.
    Entity_and_Attribute_Overview:
    Graphic image file: Printable profiles are available as GIF images. The line navigation maps and trackline maps are JPEG images. The trackline maps contain links to the seismic profiles.
    Entity_and_Attribute_Overview:
    Navigation file: Navigation files are available as ASCII text files. Provided are raw (unprocessed) shotpoint navigation files, processed shotpoint navigation files, and processed 500-shot-interval location files.
    Entity_and_Attribute_Overview:
    GIS file: The GIS project used to create the trackline maps is provided as a .zip file composed of ESRI map documents, shapefiles, and metadata.
    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, no. 2, p. 344-352. Also available on-line at http://www.seg.org/publications/tech-stand/.
    Entity_and_Attribute_Detail_Citation:
    Zihlman, F.N., 1992, DUMPSEGY V1.0: A program to examine the contents of SEG-Y disk-image seismic data: U.S. Geological Survey Open-File Report 92-590, 28 p. Also available on-line at http://pubs.er.usgs.gov/usgspubs/ofr/ofr92590.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Arnell S. Harrison
    • Shawn V. Dadisman
    • Amy Swancar
    • Ann B. Tihansky
    • James G. Flocks
    • Dana S. Wiese
  2. Who also contributed to the data set?
    Funding and (or) support for this study were provided by the USGS Water Resources Discipline (Central Highlands Lakes project - FL59100), Coastal and Marine Geology Program, and the SWFWMD. This document was improved by the reviews of Chandra Dreher (Jacobs Technology Inc.) and Nathan Smiley (USGS) of the FISC in St. Petersburg, FL.
  3. To whom should users address questions about the data?
    Amy Swancar
    Hydrologist
    10500 University Center Drive, Suite 215
    Tampa, FL
    USA

    (813) 975-8620, ext. 118 (voice)
    aswancar@usgs.gov

Why was the data set created?

The data archived here were collected as part of the Central Highlands Lakes project, which is part of a larger USGS Lakes and Coastal Aquifers (LCA) study.

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: 2007 (process 1 of 5)
    Boomer processing: These data were originally recorded in Delph Seismic format on MO discs. They were later converted to SEG-Y format using Delph Seismic processing software and archived onto compact disc. The original trace files for line WR896_2 were each divided into two or more trace files (for example, WR896_2 became WR896_2a and WR896_2b) because the original total number of traces exceeded the maximum allowed by the processing software. The SEG-Y data were processed with Seismic Unix to produce GIF images of the seismic profiles included in this report. A representative boomer processing sequence consisted of (1) running a bandpass filter of 300-500-2500-3000 Hz, (2) applying automatic gain control, (3) displaying PostScript, and (4) converting of PostScript image to a GIF image.
    Date: 2007 (process 2 of 5)
    Navigation processing: Shotpoint navigation files and 500-shot-interval location files were extracted from the trace headers of each line using Seismic Unix software. The navigation files were then processed with PROJ.4 software (http://www.remotesensing.org/proj/) to generate UTM coordinates from latitude and longitude coordinates and reformatted for use with Environmental Systems Research Institute (ESRI) GIS software.
    Date: 2007 (process 3 of 5)
    Trackline map creation: The trackline maps provided in this archive were created using the Points to Lines ArcScript (D. Rathert, http://arcscripts.esri.com/details.asp?dbid=12702) along with ESRI ArcGIS 9.2 software and then exported to Adobe Illustrator for further editing. The maps were later converted into JPEG format by Adobe GoLive. Please see the ARC readme file for detailed information about the GIS files used in this report.
    Date: 2007 (process 4 of 5)
    Data Series preparation: In addition to the process steps described above, the following steps were taken to produce this Data Series report: the handwritten cruise log was scanned and saved as a PDF file, digital logs were created using the cruise log and personal accounts of the crew members and saved as PDF files, and an HTML-based format was used to present the various parts of this archive.
    Date: 24-Jan-2017 (process 5 of 5)
    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
  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. Visual inspection of the images rendered from the data did not show any major anomalies.
  2. How accurate are the geographic locations?
    As the seismic reflection data were acquired, the position of the vessel was continuously determined by a Rockwell PLGR GPS receiver, which is accurate to within 3 to 5 m. Positions were recorded and written to the trace headers in latitude and longitude coordinates about every 60 s. The ASCII navigation files and trackline maps have not been corrected to reflect the approximately 6-m offset between the boomer and GPS antenna. Refer to figure 1 included with this archive for a diagram of the acquisition geometry, including the GPS offset measurements. NOTE: The navigation data written to the "Source coordinates" SEG-Y trace headers (bytes 73 - 80) were used to create the trackline maps; however, these data are only accurate within 1 s of arc, or 32 m. Additional navigation data were recorded more accurately to the "Unassigned" trace headers (bytes 181 - 240) by the Delph Seismic acquisition software. Please see the SEG-Y Format page for a detailed description of the SEG-Y data format including byte number assignments and header value descriptions. The Delph Seismic navigation data can be accessed from the Navigation page under the Raw Shotpoint Navigation section.
  3. How accurate are the heights or depths?
    Boomer data are relative to lake level. However, varying recorded static shifts of the data have been known to occur. Therefore, these data are not to be used for bathymetry.
  4. Where are the gaps in the data? What is missing?
    These data are collected along tracklines (2-D) and are therefore inherently incomplete. Geologic details between lines must be inferred. Although lines WR896_1 through WR896_4 are recorded in the logbook, only lines WR896_1 and WR896_2 were recovered and archived with this report.
  5. How consistent are the relationships among the observations, including topology?
    This data set is from one cruise with consistent 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 and Southwest Florida Water Management District (SWFWMD) request to be acknowledged as originators of the data in future products or derivative research.
  1. Who distributes the data set? (Distributor 1 of 1)
    Shawn Dadisman
    U.S. Geological Survey
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 803-8747, ext. 3029 (voice)
    sdadisman@usgs.gov
    Contact_Instructions: All of this report is available on-line.
  2. What's the catalog number I need to order this data set? U.S. Geological Survey Data Series 346
  3. What legal disclaimers am I supposed to read?
    This CD publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  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 3,600-byte reel identification header, with the first 3,200 bytes consisting of an ASCII header block followed by a 400-byte binary header block, both of which include information specific to line and reel number; a trace data block that follows the reel identification header, with the first 240 bytes of each trace block consisting of the binary trace identification header; and seismic data samples that follow the trace identification header. in format SEG-Y Size: 122
      Media you can order: CD (format ISO 9660)
      Note: UNIX, Linux, DOS, Macintosh
      Data format: The GIS project used to create the trackline maps is composed of map documents, shapefiles, and metadata. Map documents were created with ESRI ArcGIS 9.2 software. The shapefiles provided may also be viewed using other versions of ArcView, ArcGIS, or public domain software ArcExplorer (http://www.esri.com/software/arcexplorer/index.html). in format map document, shapefile, metadata Size: 45.0
      Network links: https://pubs.usgs.gov/ds/346/software/arc/arc.zip
      Data format: The SEG-Y standard format (Barry and others, 1975) consists of the following: a 3,600-byte reel identification header, with the first 3,200 bytes consisting of an ASCII header block followed by a 400-byte binary header block, both of which include information specific to line and reel number; a trace data block that follows the reel identification header, with the first 240 bytes of each trace block consisting of the binary trace identification header; and seismic data samples that follow the trace identification header. in format Download SEGY data Size: 122
      Network links: https://pubs.usgs.gov/ds/346/segy/
    • Cost to order the data: Prices vary.

    • Special instructions:
      Publications are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225-0046 (telephone: 1-888-ASK-USGS, e-mail: 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 public domain software Seismic Unix (http://www.cwp.mines.edu/cwpcodes/index.html).

Who wrote the metadata?

Dates:
Last modified: 19-Mar-2019
Metadata author:
Arnell Harrison
Jacobs Technology Inc., contracted with the U.S. Geological Survey
Geologist
600 4th Street South
St. Petersburg, FL
USA

(727) 803-8747, ext. 3111 (voice)
aharrison@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/ds-346metadata.faq.html>
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