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.

Explosives

70 Electric detonators were drawn from the Scott Base explosive magazine. The remaining twenty detonators, AN60 gelignite - two 50 lb boxes and 1.5 reels of detonating cord were drawn from the explosive store at Butter Point.

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Communications

Two hand held Tait VHF radios with a chit-chat channel were required when shot-point and the mid geophone spread logging point were over 1 km apart. These were available most of the time.

Weather

As K045 was based at Butter Point when in the field, the weather was logged either by the drill site party or the Event dismantling Butter Point camp. Weather was good enough however that no work days were directly lost to bad weather.

Itinerary

Thursday 6th November to Wednesday 12th- waiting at Christchurch for weather to clear.

Wednesday 12th- Arrived at Scott Base.

Thursday 13th- Following the arrival of Jack Hoffman proceeded in Haaglund to Butter Point.

Friday 14th- Unpacking and testing gear at CIROS-1 drill site.

Saturday 15th- Preparation for velocity logging of hole. Started well-shoot at midnight manually lowering the cable the first 200 metres.

Sunday 16th- After shooting several levels the cable was retrieved to chock the cause of noise. After deciding the noise was unavoidable lowered cable and started logging again. Logging was abandoned mid-afternoon after encountering a cave-in of the hole 318 metres sub-seafloor.

Monday 17th- was spent resting.

Tuesday 18th- Testing the Bolt 1900 airgun. Some problems with seals necessitated stripping and reassembly of the Bolt airgun in a heated laboratory before it would fire.

Wednesday 19th- Geophone spread laid out and ice auger set up at first shot point in preparation for overnight survey. Abandoned when Haaglund does not arrive.

Thursday 20th- Haaglund only available for four hours during which one hole was shot with explosive and airgun on a line towards MSSTS-1 drill hole.

Friday 21st- The Haaglund, scheduled for 10 a.m. arrival and survey, postponed to Saturday morning. A third string of geophones was laid out to facilitate surveying on Saturday.

Saturday 22nd- Haaglund being repaired, arrival postponed.

Surveying started using the Toyota HiLux and Ford pickup truck. 12 holes shot.

Sunday 23rd- Haaglund being repaired, arrival postponed.

Drilled 4 holes and laid out next geophone spreads. Toyota HiLux and Tait radios required in the afternoon for Butter Point relocation survey.

Monday 24th- Haaglund being repaired, arrival postponed.

18 holes shot.

Tuesday 25th- Haaglund being repaired, arrival postponed.

Informed it was unlikely to turn up at all. Request manpower assistance for airgun work to arrive on the next cargo train. Three holes were shot before the VUW Nimbus fails. All subsequent holes now needed to be double-shot. As the line was now amongst rough ice it was decided to move to the second line at right angles, heading landward towards Butter Point from the CIROS-1 drill site.

Wednesday 26th- 10.5 more holes are drilled and shot exhausting the detonator supply.

Thursday 27th- Arrival of two assistants from Scott Base means airguns can be tested as sound source. The whole day is spent unsuccessfully trying to get either airgun operating. Only subsequent to heating up at Butter Point was the VUW free-running page 22 airgun fired in the evening. Even then it was not operating as expected.

Friday 28th- Surveying resumed using VUW airgun and a jury-rigged air supply arrangement. Air consumption per shot deteriorated during the morning such that eventually about one hour was spent charging air tanks prior to shooting each hole. Pour holes were shot twice with 6 or 12 fold stacked firings of the airgun. Surveying was discontinued at 1.30 p.m. Equipment was loaded on sledges and towed to Scott Base by the D4 bulldozer overnight.

Tuesday 2nd December- The party returned to New Zealand.

Cargo