"GREATEST SHOW ON EARTH"

New Zealand Listener, Volume 13, Issue 324, 7 September 1945, Page 6

"GREATEST SHOW ON EARTH"

A Visit To Ruapehu tr

Written for "The Listener’ |

by

JAMES

HARRIS

-- S the train neared National Park I stared from the dark carriage trying to see the volcano, but the night was so black that nothing could be made out beyond the range of some light which spilled out from tHe carriage in front. Then I just managed to distinguish a dark cloud above where I thought the mountain should be, and as I watched a streak of greenish lightning pierced the northern end of the cloud. In the morning, when I came out of doors and looked through the beechtrees, the top of the mountain was shining white among little pale-grey clouds, and from over the rim a _ pinkish-grey smoke rolled upwards in the shape of a cauliflower. Then clouds formed over the snow and the volcanic’ action was hidden. ue Ea as HE "Cauliflowers," which from the plain seem to go up silently most of the time, and once or twice a day with a@ considerable bang, are fascinating to watch and have no doubt caused many near-by settlers to burn the toast, miss their dinners, and let the sheep into the wrong paddock. First of all the ashcloud shows above the edge of the crater looking like a pink or brown brain, and slowly grows up like a cauliflower on a broad stalk, the outside parts curling down while the centre rises, much as a growing leafless cauliflower might be expected to look in accelerated motion. It all seems very slow, and yet in less than a@ minute the turmoil of ash may be as high again as the mountain, and the mountain stands a good 6,000 feet above i

the surrounding plain. Sometimes the things mushroom up at quite regular intervals, and drift down-wind towards Taihape or somewhere in a regular even row. For people in the ‘National Park area the westerly winds which blow the ash over towards Hawke’s Bay are much to be preferred, as with these blowing they can proudly admire their lively mountain without having their rain come down dirty, their creeks made to taste like photographic fixing-solution and their skislopes made unusable. When the wind is westerly the only ash which comes down locatly falls and blows about on the Onetapu Desert, and no one minds about that, even if the end of the plume is making the washing dirty away in the direction of Hastings. In general, people living near the volcano seem to worry about it much less than do those who live further away. : * * RE you going to the top? Good-on-yer!" said someone. "It’s all right so long as she doesn’t blow up and get

you, that’s the only trouble.’ And when a fine day came I got a lift up the mountain track to the Salt Hut in what is probably the most valuable motor truck in the Dominion, a vehicle full of amplifiers and recording gear belonging to the Geophysical Survey. In it we climbed a road which soon left the beech trees of the bush for tussock, scrub-covered bog, and then the rocky desert of Scoria Flat. I had been at Scoria Flat alone, after breakfast alone, on VJ Day’s morn-ing-after, and had been rewarded for my trouble by seeing Ruapehu fire her big gun, sending out an echoing report as of a 12-incher, followed by the growth of a most tremendous "cauliflower" which was soon too big to photograph even from that distance. The first snow was here on the Flat, small roadside drifts almost black with volcanic ash. Then the snow on the toad became continuous, and soon we arrived. The climbing party adjusted loads between their four packs and the two geophysicists began running out cable, intending to plant a special microphone, a geophone, up on the mountain and connect it to the recording gear in the truck to take a sort of electro-cardio-graph of the volcano’s pulse. The scenery round the Salt Hut was quite extraordinary. Ash falling on this ‘side of the mountain on the previous day had so darkened the snow that f kept on trying to take off the dark glasses which I had not got on. The effect was of a very bad plaster movie-set of a mountain, Through this unreal landscape we set off on our climb. Up above, small shortstalked "cauliflowers" grew out of the crater and moved down-wind to the northeast almost with regularity, and behind us the truck’s klaxon flooded the mountain | with efficient morse as one geophysicist made remarks to another half-a-mile off. * * * HERE is one thing that every raw beginner knows about snow mountains, — and that is that one must never never — roll a snowball down, because it will gtow and grow — the famous snowball

effect -- and when it gets big enough cause an avalanche. Such literary knowledge must needs be applied, and so when the guide was not looking a hard snowball the size of a penny bread-roll went smartly down the slope in a place where an avalanche would do no harm, Rapidly it grew and grew to the size of a fourpenny coffee-bun, flopped over on its side and stopped. So much for literary knowledge. a * * OR three hours the guide led us upwards through a scene which was largely colourless, but when colour did appear, as in an amphitheatre of red rocks, the effect against the grey snow and black stones was striking... Down below the pools of the bogland glistened in the sun. Northwards the inactive cone of Ngauruhoe was all soiled by our mountain, while far over to the east. across an unmoving sea of cloud, the cone of Egmont stood up white and superior in his place of legendary exile. Up and ahead our mountain continued to pump out dirt. We went on and on through the darkened snow, and as we went higher breath became shorter. I found myself treading in other’s footsteps, playing’ Page to the guide’s Good King Wenceslas. Also I found that the only tune I knew to hum which set a reasonable pace was that thing of mixed moods, Gounod’s:* "Funeral March of a Marionette," & The: Feicano threw up a big one. We came to the glacier fai be hic long climb. It ‘was a strange ‘aij t, the big smooth slope’ being ‘striped — right across by dark bands of aah’ on ‘the snow, each a couple of yards wide: In the summer, crevasses opén up, but now snow had smoothed out the whole area, and there was just ‘a broad ‘smooth slope going up and over the crater. As we trudged: up through ‘the patterned carpet of. wet ash and snow the. mountain, did not seem so active, and only small and gentle clouds of ash were "pushing, up into view above the crest. "The calm (continued on next page)

(continued from previous page) béfore the storm," I .wanted to say, but being the lame duck of the party, had no one to say it to. * ae x ‘THE steepness eased off, and I could hear a sound like locomotives blowing off steam. The others were over the crest of the glacier and about a hundred yards from the vents when she went up. There was a roaring explosion and a brown column of dirt grew up and filled the sky. Phe thing seemed too big to be worth running away from. It would be like a very small*Mickey Mouse running away from a very large giant. But as the roating turmoil grew larger and largef, the experts in front, guide and geologists, began to run across the glacier, so I began to run too. Boulders about three feet across, trailing small stuff behind them, came out of the side of the thing in neat parabolic curves. There was a clatter of falling stones in the crater, and a continuous crackling of lightning in the swirling clouds of dirt which filled the sky. The thing was almost overhead now, but nothing more seemed to be dropping out of it. By the time we had all run 50 yards and gathered together, the highest ash must have been 4,000 or 5,000 feet above our heads, and still rising like an unballasted balloon. In the place where the forward members of the party had been when they started ‘to run, we later found many holes in the ice where hot boulders had melted their way down. One of them was big enough for three men to get right in while I took a picture, and another hole, which fortunately no one jumped into, went right through into a crevasse. * * * E took some pictures and began to freeze in a bitter wind. Food was suggested, and we ate bitterly frozen sandwiches. Then in company with members of the Ruapehu Ski Club and others, our party went up the part of the crater ridge called Paretetaitonga; on to the second highest peak of Ruapehu. Here we were upwind of the volcanic activity and the place was free of boulder craters, which at least meant that it had not been hit recently. From Paretetaitonga we looked down on the circular hole which had once held

the crater-lake. Now it held a level disc of solidified lava, in which a number of immense smoke-candles seemed to be set. A few gushed white smoke, presumed to be pure steam, and steam rose near the face of the glacier. Near the centre of the circle there was a powerful gusher of pink smoke, while vents in the far half of the area sent up a dense background of brown. A very busy vent near the base of the ridge sent up a greyish outpouring, and in among the voluminous brown background black explosions went up every few minutes, sending out stones in silhouette against the snow. while above the stones lightning-riddled tumultuous clouds periodically obscured a daytime moon. By analogy with the bagpipes one came to think of the continuous vents, responsible for the steady streaming of ash over the lip of the crater as the drones, and of the explosive vent which sent up ‘"‘cauliflowers" as the chanter. From the top of the mountain- the world looked very large, and the activity in the crater, immense as it was, did not look quite immense enough to be a manifestation of the earth’s fiery centre. In any case, modern theory rejects the fiery centre and accounts for volcanoes by

saying that certain deep rocks are forced up from below by great pressure even though solid, passing through faults in the surface rock. Near the surface the release of pressure allows certain dissolved gases to escape and combine with the oxygen of weathered surface rocks. This burning of gases from the rocks to form steam and other products maintains the heat of the "volcanic furnace," and so keeps the top of the rising rock, the lava, in a plastic condition. This allows more gases to be released, and so the volcano maintains itself rather in the way in which the heat of a candle-flame melts more wax. With a volcano, though, there is no snuffing the wick if the wax begins to run over as a lava flow. * * * ~RUPTIONS, like diseases, are neatly classified according to their symptoms. When one watches Ruapehu’s present activity, it is seen to correspond very closely to the definition of Vulcanian Activity as defined by Wellington’s Professor C. A. Cotton: "The lava is very viscous, and does not long remain liquid in contact with the atmosphere,* but consolidates in the crater. The phenomena of eruption are explosive. Much fine ash is emitted, and ash-laden gases ascend so as to form voluminous ‘cauliflower’ clouds; the ash is distributed widely by winds. ‘Breadcrust’ bombs and angular blocks, both derived from new lava in the crater, are thrown out, together with fragments of the old lavas and the debris of prevolcanic rocks." Whatever the theory, the view from Paretetaitonga was the greatest show on earth. We must have watched for about two hours without feeling the cold before being warned we would have to hurry to be back at the truck before darkness. When we did get down and relieved the anxiety of the two geophysicists, the light had gone. They had | noticed with alarm that the big one had gone up at just the time we were due at the crater. Carefully we stowed ice-axes, cameras and skis in the valuable truck, and rumbled down the rocky road towards unfrozen food, hot baths, and the evening mail from home;