(Note: Event 12 was based on USCG icebreaker "Glacier". Field notes are therefore not presented as for other Scott Base supported field events.)

WEATHER AND SEA CONDITIONS

Fine weather and calm seas were experienced throughout the survey. Temperatures were rather low for the time of year (min. −15°C). The sea ice had broken out from most of the Sound except on the western side. The surveys were prevented in New Harbour and Granite Harbour by very close pack ice.

OPERATIONAL PROBLEMS

Icing of the pressurised air system of the airgun, and ship generated electrical noise, were the main problems. Despite siting the compressor in the wet lab. corridor for warmth, freezing of the airline between compressor and firing board, and also at the firing board itself regularly occurred. This problem was partially overcome by running an electrical heater near the firing board. Both the seismic arrays and the magnetometer were subject to electrical noise pickup, which in the case of the magnetometer resulted in the collection of very little useful data. Apart from 60 Hz noise, intermittent noise from motor drives and other sources, and radio transmissions caused interference problems at times. However, it will be possible to remove most of this noise from the seismic data on replay of the tapes.