| Description |
This DVD-ROM contains copies of the navigation and field chirp subbottom data collected aboard the R/V Seaward Explorer, from 7-25 May, 1995. The coverage is in the New York Bight area. 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. For more information on the seismic surveys see https://cmgds.marine.usgs.gov/fan_info.php?fan=1995-007-FA These data are also available via GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean ( http://www.virtualocean.org/) earth science exploration and visualization applications. [More]
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