CP2 Regional Sea Boundaries: Atlantic North-West Approaches, Rockall Trough and Faeroe/Shetland Channel, Offshore 1:250k: Anton Dohrn, George Bligh Bank, Harker, Kennedy, McCallien, Rockall Island, Offshore 1:500k: Central Hatton, Central Rockall Basin, North Hatton, North Rockall Basin, SeaVoX Sub-Ocean: NORTHEAST ATLANTIC OCEAN (40W)
This geophysical survey has been carried out by Digicon Geophysical, for British Geological Survey (BGS), the Multichannel Deep Seismic survey took place from July to August 1993 in the Rockall area on board the MV Acadian Searcher. The purpose was to collect data as part of Rockall Continental Margin Project: 1) to shoot a grid of lines on eastern flank of Rockall Bank; 2) to shot three long transect lines across Rockall Bank and the Rockall-Hatton Basin down to 18sec two-way time; 3) to acquire gravity data. Sub-bottom profiling data were collected using Airguns. Gravity data were collected. These data were recorded digitally and are archived by BGS. Technical details of the survey are contained in BGS report WB/93/28C and contractor report. GeoIndex Offshore - https://mapapps2.bgs.ac.uk/geoindex_offshore/home.html?cruise=1993/2_RCK&.
NAVIGATION: Skyfix, Differential GPS, WGS-84, Universal Transverse Mercator Zone 28N CM 15W. SEISMIC AIRGUN: 1726.825km (Grid:1065.67km, Transect: 661.15km): Single Tuned Point Source Array, Bolt 1500LL and 1900C airguns, 4 strings of 10,50m wide array. Operating Pressure 1900 psi (min1800psi). Grid: 24 Active guns, 16 spare, array volume 6360 cu in., (min 5410 cu in). Transect: 40 active guns, array volume 9300 cu in., (min 7900 cu in). Array depth: 10+1m. Gun timing system: Digitcon CLASSII. Multi-channel Streamer: 240 groups, 25m group length and interval, total length 6000m, depth 15m +2m, Hydrophone: DG-018 acceleration-cancelling (14 per group), Sample rate: 2 milliseconds and 4 milliseconds, 8 compasses, Digicourse 318 or 321 in-line compass sections. Digicon DSS-240 seismic data acquisition system. Record format: Demultiplexed SEG-Y @ 6250 bpi IBM floating point, tape drives: Telex tri-density(125ips @6250 bpi), Recording parameters: Grid: Record length 10 sec, Sample rate 2ms, Low cut filter 3Hz, High cut filter 160 Hz,Fold coverage 60, Number of Runoff shots 63, Shotpoint intervals 50m, Single Trace Plotter. Trace near 4. Plots every 41 shots, Nav log tape, Single data trace – Quietest of near 4. Transect: Record length 18 sec, Sample rate 4ms, Low cut filter 3Hz, High cut filter 80 Hz,Fold coverage 120, Number of Runoff shots 125, Shotpoint intervals 25m, Single Trace Plotter. Trace near 4. Plots every 41 shots, Nav log tape, Single data trace – Quietest of near 4. On board seismic data processing: Advance Geophysical PROMAX on an IBM340. Brute stacks produced for Grid survey and Transect lines. GRAVITY: Lacoste and Romberg S-75 fitted with a J & K interface box and using Co-operator v3.62 software, all lines except the latter half of D13 and first half of D15. Grid: recorded at 10 second interval. Transect: recorded at 5 second interval. Base ties, field cross-tie calculations. For more detailed information on the acquisition equipment and data collection techniques, operational standards, data processing methods and quality control procedures used on this survey see the Report of Survey/Cruise Report and associated documentation where available. The information available may vary depending on the age of the survey. Data are checked and loaded to the BGS Coastal and Marine data management system following BGS marine data management procedures.
unrestricted use, copyright acknowledgement
Geophysical Survey 1993/2_RCK: Northern Rockall Trough and adjacent areas (04/07/1993 to 14/08/1993)
Airgun/Sleeve Gun, CHIRP Sub-bottom Profiler, Echo Sounder, Gravimeter
Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced British Geological Survey materials "Contains British Geological Survey materials ©UKRI [year]"