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.
Location
Deep Water Dump Site DWDS 106, Continental Rise offshore New Jersey, New York, United States, North America, North Atlantic;
Summary
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).
