Other ID: 251
Organization(s): USGS, Woods Hole Coastal and Marine Science Center
Principal Investigator(s): James M. Robb
Data Type(s): Location-Elevation: Navigation, Seismics: Sub Bottom Profiler, Sonar: Sidescan
Scientific Purpose/Goals: Sidescan sonar imaging of the ocean bottom around the DWDS-106 Municipal Sludge dumpsite, for support of DSRV ALVIN dives and to characterize sea-floor microtopography.
Start Port/Location: Woods Hole, MA
End Port/Location: Woods Hole, MA
Start Date: 1992-07-20
End Date: 1992-07-29
Equipment Used: Sidescan sonar, GPS (wh), Loran-C, 3.5 kHz
Information to be Derived:
Summary of Activity and Data Gathered: AMS-120 sidescan unit with the Qmips processing system functioned very well, with only 4 hours lost when a wire termination failed apparently due to tow strumming. Site surveys were accomplished at 4 off-dumpsite sites, and two areas within the dumpsite study area were imaged and mosaicked while at sea. The data commonly show features indicating offshore-directed bottom flows. A control site (2600 m at 70 deg 40 min W) and 2 sampling sites SW of the main study area show a smooth ocean bottom, with minor flow indications, such as elongated moats or dune structures. Within the study area, in contrast, our 8-line mosaic shows striking offshore lineations, evidently erosional furrows (parts were observed last year using Jason), as well as smooth bottom where a tongue of muddy sediments overlies the furrowed surface. The furrows lie downslope from where canyons debouch. Also mosaicked with three lines was a rough area of greater relief and high backscatter that may be part of a large olistostrome (landslide block).
Staff: Jana DaSilva, William Danforth, Jane Denny, Molly Gowen, Thomas O'Brien, James M. Robb, William Schwab, Melissa Walden
Notes: Project = DWDS-106 Sewage Sludge Investigation, DWDS-106 Sewage Sludge Investigation
Deep Water Dump Site DWDS 106, Continental Rise offshore New Jersey, New York, United States, North America, North Atlantic;