Scientific Endeavours

The methodology was to add TV surveillance and an LPH geophone to the existing IMESS telemetry net, and read the onset times of signals from each eruption. After R.D.R.C. had approved the proposal, NSF declined to fund Prof. Kienle's proposal to continue operating the net, or to let him remove it. He agreed that I could operate and maintain 4 seismic stations. Antarctic Division cleared this with NSF.

Purchase and cold testing of equipment began on 1 June 1986. The prototype Philips CCD camera LDH 0600 with Cosmicar C1614EX-2 autofocus lens rated to −25°C, developed a fault at −10°C, but continued working to the end of the test at −40°C. A replacement was ordered from the French factory in August but had not arrived by the time I flew south on 18 November.

Also of concern was that NSF belatedly decided to remove the IMESS net. Prof. Kienle persuaded them to leave me the top 2 stations, and advised me by telex on 21 October 1986.

On 19 November, the helicopter scheduled to service the low level stations was requested to make a high level reconnaissance of the route to the TV site, and drop equipment at the lower hut on Erebus. Messrs Dibble, Wendon, and James Barker were briefly landed there, but it was discovered that the hut was above the new landing limit of 12,000 ft pressure altitude, and the pilot was disciplined to ensure no further landings were made. My programme could now be carried out only by flying toboggans to Fang acclimatisation site, and driving up with the equipment. The decision to support this was delayed until Phil Kyle arrived on 26 November, and until then, I installed the TV receiving/recording equipment, overhauled the IMESS receivers, and improved the real time detection ability of the windless Bight Infrasonic array to Erebus eruptions.

Prof. Kyle said that NSF Washington was awaiting a request from me to borrow the top IMESS stations. El and Cones (sent via Ant. Div., 27 November), and had approval to operate 3 himself. He suggested that we go up Erebus together as independent parties, and he offered to take up the extra gear we needed for a base camp at Fang, so that we would not exceed out helo hours. The OIC then agreed to us taking the Grizzly toboggan I had always claimed was necessary, and with 4 U.S. Bombardiers as well, we flew to Fang on 3 December. All equipment, people, and most stores were carried up on Bombardiers by 6 December, using the route on the attached aerial photo. The Grizzly developed a slipping clutch due to missing bearing pads on the driven variator, and was left at Fang. The 2 Yamaha 300 which belong at the hut, could not climb steep hills or carry loads, and without Phil Kyle's unstinting help, we could not have gotten our equipment up. without the Grizzly, Kyle would not hove welcomed us on the mountain.

On 8 December, Bill McIntosh, Wendon and I blazed a toboggan route to within 100 m of the east rim of the crater, (Figure 4) and all 385 kg of TV equipment was installed there by 10 December (Figure 5). The new camera arrived, and was installed in a rugged insulated housing on a tripod, designed to withstand being hit by small bombs. The auto-iris oscillated until it was driven from video-out instead of iris-out.

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The line scan would only start when the power plug was pushed into the camera body to get a fast turn-on. These problems, and difficulties in talking direct to the Science Lab by radio delayed TV operation until the last day the OIC would allow us on Erebus, and prevented me applying demisting techniques to the camera. My portable TV receiver and the NIPR portable oscilloscope proved essential.

A TRS power cable and polyethylene video cable were buried for 200 m around the rim to the BCNZ 400mw BCTTX transmitter on Ch 9. Dual Yagi 5 element antennae were used on a 2.4 m mast. The power supply placed midway, consists of 8 Donley 12V Gel/cell batteries of 60AH capacity in parallel, charged by a 42W Solarex panel. The total load is 4W. A switch disconnects the camera/transmitter when the battery is nearly flat, and reconnects as it recharges. Unfortunately, the camera may not restart.

While Dibble and Barrett were installing the TV, Miura and Wendon were measuring infrared temperatures in the crater from 4 points around the rim, using a Minolta IR-0510 thermometer with 1° beam, operating in the 8-14 micrometer band, and a digital recorder. They marked the measurement points on Polaroid photos, so measurements could be repeated. About 5 readings were made of each of 81 points.

On 13 December we serviced infrasonic microphones at El and Cones, and added 3 60AH gel/cells to the El battery. Mr. Miura installed a radial LPH geophone (T-4s) at El to find if there was a VLF seismic precursor corresponding to the infrasonic one. Then we received a reply from Washington declining to lend us El and Cones, but decided not to remove our equipment. We started down on the 17th and reached Scott Base on 18 December.

Meanwhile, Dr. Kaminuma was doing playback at Scott Base, and helping Mr. Denyer monitor the TV. He also recorded gravity tides on NIPR equipment. After our return, he instructed Barrett in the playback equipment, and in how the IMESS data had been analysed in Japan. He also made gravity surveys of the Dry Valleys, Dailey Is., and at Cape Bird as an NIPR project, taking Miura and Barrett with him.

Dr. Dibble's first priority on descending was to mitigate the threatened removal of NSF equipment from Scott Base, following NSF's decision not to lend it. Dr. Kyle had hoped the equipment could stay, but otherwise to put it in the "Little House" near Scott Base, and still connect it to the recorders at Scott Base. Dr. Dibble prepared cables for this before returning to NZ on 21 December, a day ahead of schedule.

Dr. Kaminuma and Mr. Miura returned to NZ on 7 January 1987, the day NSF shifted their equipment to McMurdo. Mr. Barrett continued with playback, and analysing the data, while in NZ, Dibble searched for replacement telemetry receivers. They were ordered on 9 January with promise of rapid delivery, and agreement that Barrett could stay to help install them, and resume IMEEMS, but by the 19 January deadline set by the OIC, the crystals had not arrived. The receivers were sent without crystals, and Barrett returned to NZ on 22 January, 14 days ahead of schedule.