Deep-towed chirp profiles of the Blake Ridge collapse structure collected on USGS cruises 92023 and 95023 aboard the R/V Cape Hatteras in 1992 and 1995

This CD-ROM contains copies of the navigation and deep-towed chirp
subbottom data collected aboard the R/V Cape Hatteras on cruises 92023 and
95023 in 1992 and 1995 respectively. This CD-ROM is (Compact Disc-Read
Only Memory UDF (Universal Disc Format) CD-ROM Standard (ISO 9660
equivalent). 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 CD-ROM. These links
are only accessible if access to the Internet is available during browsing
of the CD-ROM.
On cruise 92023, 58 km of deep-towed chirp data were recorded on 4 lines
and broken into a total of 8 files. 78 square kilometers of sidescan
mosaic and approximately 1000 km of air gun single channel seismic
reflection data were recorded as well but are not achived on this report.
On cruise 95023, 100km of deep- towed chirp data were recorded on 5 lines
and broken into 18 files. 152 square kilometers of sidescan mosaic and
244.3 km of GI gun single channel seismic reflection were also recorded
but are not archived on this report.
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).