British Geological Survey (BGS) Geophysical Survey 1969/7: North Irish Sea (11/10/1969 to 28/10/1969)

Report: Tully, MC. 1970. North Channel Irish Sea Cruise Report. MGU Project 69/07. (IGS Report No. 10) Navigation: Decca Mk 12 Main Chain. Equipment: EG&G Seismic Profiling: Two sparkarrays were used firing together at 2500J and 500J respectively at just over once per second. The two arrays were used to give a greater frequency spectrum. KH Transit Sonar: Only used in latter part of the survey as the main area had been covered previously. Elsec Proton Magnetometer. MS 32 Echo-Sounder. La Coste and Romberg Air-Sea Gravity Meter. See also IGS report 71/19.