Other ID: NE-82-4
Organization(s): USGS, Woods Hole Coastal and Marine Science Center
Principal Investigator(s): Deborah Hutchinson
Data Type(s): Sonar: Single Beam, Electro-Magnetic: Magnetics, Seismics: Air Gun / Water Gun, Seismics: Boomer, Seismics: Bubble Gun, Seismics: Sparker, Seismics: Sub Bottom Profiler, Seismics: Multichannel, Location-Elevation: Navigation
Scientific Purpose/Goals: Profile across the large positive gravity anomaly which crosses Long Island Sound in order to identify basement or sub-basement structure; complete the survey begun in June 1981 to identify the southward termination of the Hartford graben in Long Island Sound; and compare profiles collected with the pre-amp 12-channel streamer and 15-inch watergun (June 1981) with those collected this cruise with the transformer 12-channel streamer and 15-inch watergun.
Start Date: 1982-06-13
Start Port/Location: Stamford, CT
End Date: 1982-06-25
End Port/Location: Cataumet, MA
Equipment Used: Raytheon DE-719 precision echo sounder, Geometrics G-856 magnetometer, Water gun (wh), Teledyne 28420 hydrophone, Fairfield Industries 120 m and 240 m streamer, Multichannel seismics, Northstar 6000 LORAN-C
Information to be Derived:
Summary of Activity and Data Gathered: The near trace monitor record across the gravity high (Line 7A) using the 80 cu. in. watergun shows no convincing sub-basement reflectors. However, the low frequencies and multiples make the record difficult to read. Several additional crossings of the large valley south of New Haven that we first profiled in June 1981 show that this potential continuation of the Hartford graben turns southward toward Stratford shoal. The valley loses its distinct cut-out shape and many widen and shallow toward the shoal, making it difficult to distinguish reflectors other than the coastal plain and basement surfaces. However, our present grid of profiles should be sufficient to locate the graben if it continues under the shoal using the processed data. Fathometer data: 185.2 km; Magnetometer data: 28.0 km; 80 cu. in. watergun data: 102.6 km (12-channel 10-m groups), 14.2 km (200-element streamer); 15 cu. in. watergun: 65.8 km (12-channel 10-m groups), 2.6 km (12-channel 20-m groups); Reflection data; Magnetic data.
Staff: Deborah Hutchinson, David Mason, Gregory Miller, Arnold O. Tanner
Notes: Original Center People field contained: Debbie Hutchinson - Ch. Sci.; Greg Miller - DFS V technician; David Mason - Boat Operator/Gun technician; Arnold Tanner - Shore support/watch.
Long Island Sound, New York, Connecticut, United States, North America, North Atlantic,