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Archive of Digital Boomer Subbottom Data Collected During USGS Cruise 05FGS01 Offshore East-Central Florida, July 17-29, 2005

By Arnell S. Forde,¹ Shawn V. Dadisman,¹ Dana S. Wiese,¹ and Daniel C. Phelps²

¹U.S. Geological Survey, St. Petersburg, FL 33701.
²Florida Geological Survey, Tallahassee, FL 32304.

U.S. Department of the Interior
U.S. Geological Survey
St. Petersburg Coastal and Marine Science Center

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).

	Page Contents: Information Statement System Requirements Getting Started Disc Organization Project Summary Acknowledgments References Cited Suggested Citation

Information Statement

This Digital Versatile Disc (DVD) 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.

System Requirements

This disc is readable on any computing platform that has standard DVD driver software installed. The minimum software requirements are a Web browser, a portable document format (PDF) reader, and a text editor. If you cannot fully access the information on this page, please contact USGS Information Services at infoservices@usgs.gov or 1-888-ASK-USGS. NOTE: The only supported Web browsers that properly display all features of the geospatially interactive profiles are Internet Explorer 6 or greater for Windows and Firefox 3.6 or greater for all platforms

Getting Started

To access the information contained on this disc, use a Web browser to open the file index.html. This report is divided into seven sections: Acronyms and Abbreviations, Disc Contents, Navigation Data and Maps, Subbottom Profiles, Field Activity Logs, FGDC Metadata, and Software. Links at the top and bottom of each page provide access to these sections. This report contains links to the USGS and collaborators or other resources that are only accessible if access to the Internet is available while viewing these documents.

Disc Organization

This disc contains a readme (2-KB text file) document, which provides a brief description of the report; a folder containing SEG Y binary data files; GIS files, and all the Hypertext Markup Language (HTML) files, folders, and images used to produce the Web pages included in this report. The Disc Contents page contains a diagram with locations and links to all files and folders contained on this disc.

Project Summary

In July of 2005, the U.S. Geological Survey (USGS), in cooperation with the Florida Geological Survey (FGS), conducted a geophysical survey of the Atlantic Ocean offshore of Florida's east coast from Flagler Beach to Daytona Beach. This report serves as an archive of unprocessed digital boomer subbottom data, trackline maps, navigation files, Geographic Information System (GIS) files, Field Activity Collection System (FACS) logs and formal Federal Geographic Data Committee (FGDC) metadata. Filtered and gained (showing a relative increase in signal amplitude) digital images of the seismic profiles are also provided. Refer to the Acronyms page for expansions of acronyms and abbreviations used in this report.

The USGS Saint Petersburg Coastal and Marine Science Center (SPCMSC) assigns a unique identifier to each cruise or field activity. For example, 05FGS01 tells us the data were collected in 2005 for cooperative work with the FGS and the data were collected during the first 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 field activity ID.

The boomer subbottom processing system consists of an acoustic energy source that is made up 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, which propagates through the water column and shallow stratrigraphy below. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), detected by the receiver (a 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 two-dimensional (2-D) vertical image of the shallow geologic structure beneath the ship track is produced. Figure 1 displays the acquisition geometry. Refer to table 1 for a summary of acquisition parameters and table 2 for trackline statistics.

The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG Y format (Barry and others, 1975), except an ASCII format is used for the first 3,200 bytes of the card image header instead of the standard EBCDIC format. For a detailed description about the recorded trace headers, refer to the SEG Y Format page. The SEG Y files may be downloaded and processed with commercial or public domain software such as Seismic Unix (Cohen and Stockwell, 2005). See the How To Download SEG Y Data page for download instructions. The printable profiles provided here are GIF images that were processed and gained using SU software; refer to the Software page for links to example SU processing scripts. The processed SEG Y data were also exported to Chesapeake Technology, Inc. (CTI) SonarWeb software to produce a geospatially interactive version of the profile that allows the user to obtain a geographic location and depth from the profile for a given cursor position; this information is displayed in the status bar of the browser. Please note that clicking on the profile image switches it to "Expanded View" (a compressed image of the entire line) and cursor tracking is not available in this mode.

The printable and geospatial profiles can be viewed from the Profiles page or from links located on the trackline map.

Detailed information about the navigation system used can be found in table 1. To view the trackline maps and navigation files, and for more information about these items, see the Navigation page.

NOTE: Due to a software malfunction, some lines were terminated early or did not have data collected; therefore, they are not included in this archive.

Acknowledgments

Funding for this study was provided by the USGS Coastal and Marine Geology Program and FGS. This document was improved by the reviews of Lisa Robbins (USGS) and Marilyn Montgomery (Jacobs Technology Inc.) of the USGS - St. Petersburg, FL.

References Cited

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/resources/publications/misc/technical-standards.

Cohen, J.K., and Stockwell, J.W., Jr., 2005, CWP/SU: Seismic Unix Release 42: A free package for seismic research and processing: Center for Wave Phenomena, Colorado School of Mines. Available on-line at http://www.cwp.mines.edu/cwpcodes/.

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.

Suggested Citation

Forde, A.S., Dadisman, S.V., Wiese, D.S., and Phelps, D.C., 2012, Archive of digital boomer subbottom data collected during USGS cruise 05FGS01 offshore east-central Florida, July 17-29, 2005: U.S. Geological Survey Data Series 647, 1 DVD.