Read-me File
Archive of Datasonics SIS-1000 Chirp Subbottom Data
Collected During USGS Cruise SEAX 95007
New York Bight, 7-25 May 1995

U.S. Geological Survey Open-File Report 01-97

by Jenna C. Hill, William C. Schwab, and David S. Foster

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


This DVD-ROM (Digital Versatile Disc-Read Only Memory) has been produced in accordance with the UDF (Universal Disc Format) DVD-ROM Standard (ISO 9660 equivalent) and is therefore capable of being read on any computing platform that has appropriate DVD-ROM driver software installed. Access to the data and information contained on this DVD-ROM was developed using the HyperText Markup Language (HTML) utilized by the World Wide Web (WWW) project. Development of the DVD-ROM documentation and user interface in HTML allows a user to access the information by using a variety of WWW information browsers (i.e. NCSA Mosaic, Netscape) to facilitate browsing and locating information and data. To access the information contained on this disk with a WWW client browser, open the file 'index.htm' at the top level directory of this DVD-ROM with your selected browser. The HTML documentation is written utilizing some HTML 4.0 enhancements. The disk should be viewable by all WWW browsers but may not properly format on some older WWW browsers.

Also, some links to USGS collaborators and other agencies are available on this DVD-ROM. These links are only accessible if access to the Internet is available during browsing of the DVD-ROM.

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.


Beginning in 1995, the USGS, in cooperation with the U.S Army Corps of Engineers (USACE), New York District, began a program to generate reconnaissance maps of the sea floor offshore of the New York-New Jersey metropolitan area, one of the most populated coastal regions of the United States. The goal of this mapping program is to provide a regional synthesis of the sea-floor environment, including a description of sedimentary environments, sediment texture, seafloor morphology, and geologic history to aid in understanding the impacts of anthropogenic activities, such as ocean dumping. This mapping effort differs from previous studies of this area by obtaining digital, sidescan sonar images that cover 100 percent of the sea floor.

This investigation was motivated by the need to develop an environmentally acceptable solution for the disposal of dredged material from the New York - New Jersey Port, by the need to identify potential sources of sand for renourishment of the southern shore of Long island, and by the opportunity to develop a better understanding of the transport and long-term fate of contaminants by investigations of the present distribution of materials discharged into the New York Bight over the last 100+ years (Schwab and others, 1997). Data collected in 1996, USGS cruise SEAX 96004, augments data collected in 1995 with sidescan sonar and seismic reflection data collected within the New York Bight Apex region. This report is an archive of the chirp seismic reflection data collected in 1995.

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 RAWNAV: This directory contains raw DGPS navigation files as the data became available during the cruise.
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.