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Open-File Report 02-045, Chirp Subbottom Data, Northeastern Gulf of Mexico, Disc 1

Title Page - Introduction - Cruise Report - Equipment - Chirp Data - Shotpoint Maps - Navigation - Pictures - Metadata


Archive of Chirp Subbottom Data
Collected During USGS Cruise ORGN 00005,
Northeastern Gulf of Mexico, 15 February - 2 March, 2000

U.S. Geological Survey Open-File Report 02-045

by Mark K. Capone, B. Ann Swift, Kathryn M. Scanlon

U.S. Geological Survey, 384 Woods Hole Rd., Woods Hole, MA 02543

Introduction - Technical Description - Directories - Disclaimer - References

In 1999, the Gulf of Mexico Fishery Management Council recommended that NOAA's National Marine Fisheries Service establish two approximately 11-square-mile areas on the shelf edge in the northeastern Gulf of Mexico as no-fishing areas. One of the areas, the Madison-Swanson Marine Protected Area (MPA) lies about 100 km south of Panama City, Florida. The second area, Steamboat Lumps MPA lies about 150 km SSE of Madison-Swanson. The high-resolution seismic-reflection data contained herein were collected as part of a larger study of the effectiveness of no-fishing reserves in protecting grouper spawning aggregations. These subbottom profiles will be used in conjunction with other data to map the seafloor geology and the character and extent of benthic habitats within and surrounding the two MPAs. They show the shape and acoustic impedence of the seafloor and the thicknesses and orientations of shallow subsurface horizons. These data may be helpful in the following applications:

  1. choosing biological monitoring sites
  2. management decisions in the MPAs
  3. choosing sites for future MPAs
  4. studies of paleo-sealevel
  5. studies of the inter-relationships between seafloor geology and benthic ecology
  6. studies of sedimentary geology and geologic framework of the northeastern Gulf of Mexico

Technical Description

The data and information on these DVD-ROMs are formatted for access and download via WWW information browser (e.g., Internet Explorer, Netscape, Opera). Hyperlink references to additional Internet-resident information (WWW) will not function if your computer is not actively connected to the Internet via ISP or online LAN. These web links are functional at publication, but there is no guarantee that they will not change or be discontinued.

The archived Chirp subbottom data are in standard Society of Exploration Geologists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded for processing with software such as Seismic Unix ( or SIOSEIS ( The subbottom data were recorded on the ISIS data acquisition system in QMIPS format. Chirp subbottom channel extracted from raw QMIPS format sonar files and converted to 16-bit Int. SEG-Y format using the program QMIPSTOSEGY. Even though the data are in SEG-Y format, it is not the conventional time series data (e.g. voltages or pressures), but rather instantaneous amplitude or envelope detected and therefore all of the amplitudes are positive (though not simply rectified). DOS and Microsoft Windows compatible software for plotting SEG-Y files (PLOTSEIS) and viewing SEG-Y headers (DUMPSEGY) is located in the PLOTSEIS directory. Processed chirp profiles (GIF images) may be viewed on this DVD-ROM with your WWW browser.


Directory BIN:
Subdirectory PLOTSEIS: This directory contains the DOS programs for plotting SEG-Y files and viewing SEG-Y headers.
Subdirectory SU: Contains the Seismic UNIX ( scripts used to process and plot the chirp subbottom data and extract shot navigation from the SEG-Y headers
Directory HTMLDOCS: Contains the necessary HTML files and supporting graphics to allow the user access to the DVD-ROM via any World Wide Web (WWW) browser.

Directory IMAGES: Contains GIF and JPEG images that are used by HTML hyperlinks.

Directory MAPS: This directory contains basemap and shot navigation themes. The data may be displayed with ARCVIEW version 3.1 or above, or ARCEXPLORER. You may need to copy the directories to disk and edit the .apr file in the PROJECT subdirectory to reflect the new directory paths.

Directory NAV:
Subdirectory SHOTNAV: Contains the shot navigation data that were collected during the cruise using a USGS differential GPS system
Directory SEGY: Contains the Chirp SEG-Y format data. These data were collected using a Datasonics SIS-1000 Chirp subbottom profiler.  The SEG-Y data were logged on a Triton-Elics ISIS acquisition system. The SEG-Y format is documented in HTML.

Directory SEISIMAG: Contains the GIF format files of the Chirp subbottom profiles generated with Seismic UNIX (


This Digital Versatile Disc-Read Only Memory (DVD-ROM) 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-ROM have been used by the 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 these data, software, or related materials.


Barry, R.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats, Geophysics, v. 40, p. 344-352

Zihlman, F.N., 1992a, DUMPSEGY V1.0: A program to examine the contents of SEG-Y disk-image seismic data; U.S. Geological Survey Open File 92-590.

Zihlman, F.N., 1992b, PLOTSEGY V1.0: A DOS graphics program to display SEG-Y disk-image seismic data; U.S. Geological Survey Open File 92-349A and 92-349B.

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Title Page - Introduction - Cruise Report - Equipment - Chirp Data - Shotpoint Maps - Navigation - Pictures - Metadata