Narrative

Event K045 was delayed in Christchurch by bad weather for five days before flying to the Antarctic on Wednesday 12th November. Following the arrival of the flight from New Zealand the next day the party proceeded to Butter Point where the CIROS-1 drill-hole, well ahead of schedule, was almost complete. There was time to unpack and check equipment before attempting the downhole velocity shoot. The well shoot was of doubtful success due primarily to unanticipated electromagnetic induction in the unshielded logging cable used. Unfortunately while there had been time prior to shipment to check transmission of signal from the hydrophone up the logging cable, work on the Nimbus recorders configuring them for twin reflection operation meant that the Nimbuses were not available for a full system test prior to shipping south. Well logging was continued in the hope that later digital filtering would render the data usable. Logging was discontinued when a hole collapse was encountered at 318 metres sub-seafloor.

For the seismic reflection work K045 planned to draw manpower support from the CIROS-1 scientific party and the leading vehicle for housing the seismic recorders was to be the Haaglund. Unfortunately due to the early completion of the CIROS-1 hole none of the scientific party were available for K045 and replacement personnel from Scott Base, due to arrive on the Haaglund, arrived only near completion of the Event due to the non-appearance of the broken-down Haaglund.

Consequently the majority of the seismic reflection work was performed by B. Davey and G. Alder rather than the four people budgeted for. The leading vehicle with heated 'cab' was the Ford pick-up truck with only two-wheel drive and broken front suspension. The extent and geometry of the lines was thus limited by the broken ice and snow-drifts beyond the fortunately large section of good sea-ice adjacent to the CIROS-1 drill site. With only two people airgun work could not be attempted and it was not until the final 1.5 days, with the arrival of 2 extra personnel from Scott Base that the airgun comparison could be atttempted. Airgun operations turned out to be full of difficulties and the first day was spent just getting the one gun, the VUW free running airgun, operating in a temporary fashion, it appeared the freezing action on air-seals and air-ducts could only be overcome by heating the airguns in heated cabs between shot operations. The Bolt airgun would only fire subsequent to being stripped in a heated laboratory.

Approximately 2.6 km of 6-fold seismic reflection line was shot on the line between CIROS-1 and MSSTS-1 with a CDP spacing of 17.5 metres. On a line running at right angles towards Butter Point approximately 2 km of 6-fold line with 35 metre CDP spacing was shot.