This marine geophysical survey took place during October 1976; March, April, December 1977 in the western English Channel and Southwest Approaches. The survey was carried out by Geophysical Service Inc on behalf of the Institute of Geological Sciences (BGS). The aim of the survey was to carry out a multichannel airgun survey. Coverage 2564Km. A short (600m, 24-section) streamer was used, and the data processed to optimise definition of horizons in the uppermost part of the section to assist interpretation of commercial deep seismic data, and to allow future drilling in this area. These data are archived by BGS. See report Seismic records SW Approaches 1976/77 (IGS deep seismic survey 1976/8) for further information.