Other ID: CH 12-92
Organization(s): USGS, Woods Hole Coastal and Marine Science Center
Location: Cape Fear slide, Blake Ridge, United States, North America, North Atlantic;
Principal Investigator(s): William Dillon, William Schwab
Data Type(s): Location-Elevation: Navigation, Seismics: Air Gun / Water Gun, Seismics: Sub Bottom Profiler
Scientific Purpose/Goals: To obtain digital seismic profiles in the area of gas hydrate development on the continental rise off North and South Carolina, and to test and obtain data from the new USGS/Datasonics deep-towed sidescan-sonar system.
Start Date: 1992-09-21
Start Port/Location: Morehead City, NC
End Date: 1992-10-04
End Port/Location: Morehead City, NC
Equipment Used: Air gun, Sidescan sonar, 3.5 kHz, Loran-C, Single channel hydrophone
Information to be Derived:
Summary of Activity and Data Gathered: Two research areas were studied; to the north at the head of the Cape Fear slide and to the south on the crest of Blake Ridge. The seismic profiling system worked perfectly and allowed collection of 163 km of excellent quality seismic data at the Cape Fear slide site and 1204 km at the Blake Ridge site. Unfortunately the outer section of the streamer was damaged during operations (presumably it went into the ship's propellers), but the damaged section was replaced by a spare section. Four sidescan sonar test lowerings were carried out. During the first 3 lowerings, only the port side provided data at operating depth. A leaking connector was identified and repaired. During the last day, the sidescan worked properly and collected 91 km data. Weather conditions prevented lowering of the sidescan for much of the cruise and one day was lost to Tropical Storm Earl.
Staff: Dwight Coleman, William Danforth, Barry Irwin, Thomas O'Brien
Anton, C., Dillon, W.P., and Lee, M., 1999, Anomalous, nearly horizontal, seismic reflection at the Blake Ridge--Evidence for a gas trap crosses the base of gas hydrate stability [abs.]: Eos, Transactions, American Geophysical Union, Spring Meeting, v. 80 no. 17-supplement, URL: http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=table&application=sm99&convert=&converthl=&refinequery=&formintern=&formextern=&transquery=dillon&_lines=&multiple=0&descriptor=%2fdata%2fepubs%2fwais%2findexes%2fsm99%2fsm99|537|3089|T51A-08%20%20Anomalous%2c%20Nearly%20Horizontal%2c%20Seismic%20Reflection%20at%20the%20Blake%20Ridge:%20Evidence%20for%20a%20Gas%20%20Trap%20that%20C%20*%20Anton%2c%20C%20H%20Dillon%2c%20W%20P%20Lee%2c|TEXT|localhost:0|%2fdata%2fepubs%2fwais%2findexes%2fsm99%2fsm99|5522885%205525974%20%2fdata2%2fepubs%2fwais%2fdata%2fsm99%2fsm99.txt.
Taylor, M.H., Dillon, William P., Anton, Christopher H., and Danforth, William, 1999, Seismic-reflection surveys of the Blake Ridge, R/V CAPE HATTERAS 1992 and 1995; data acquisition, navigation and processing: U.S. Geological Survey Open-File Report 99-372, URL: http://pubs.usgs.gov/of/1999/of99-372/.