ACTIVITY OF NGAURUHOE.

Taranaki Daily News, 12 November 1917, Page 7

ACTIVITY OF NGAURUHOE.

'PROLONGED ERUPTION. DISPLAY LASTS 18 HOURS. TREMENDOUS PLOW OF LAVA. The activity displayed by Ngauruhoe during the past 1(5 days became greatly intensified during the week-end, and from Saturday evening until Sunday afternoon there was a very violent erupH on *. O fl 'y the oldest Maoris in the district are able to recall a similar disturbance.

The outburst commenced nine o'clock on Saturday evening, and continued practically without cesalion until 3 p.m. on Sunday. Explosion followed explosion, and the protracted earth tremors that were a feature of the outburst were the cause of considerable alarm among the settlers in the vicinity. The Maoris have deserted Otuku pa, on the northern slope of Tongariro. All through the night, molten lava and large red-hot boulders were ejected from the crater. The sky for miles around was illuminated to blood-red colour, and the spectacle wag one of surpassing grandeur. There was a long series of tremendous detonations in the heart of the crater until 10.40 p.m., when a gigantic explosion occurred. It was heralded by dense volumes of smoke and steam Red-hot boulders were projected to a height of over 3000 ft, retaining their brilliant colour for some minutes after falling back to the earth. Some of them fell wide of the mountain on to the Waimarino Plains. The lava flowing down the gullies and crevasses in the mountain face also glowed a bright red, quickly losing the colour in the process of cooling. The mighty eaVth shocks were felt many miles away beyond Taumarunui. Articles on shelves at the prison camp, fully six miles from the' base of the mountain, were thrown on to the floor. Houses trembled on their foundations, and numerous panes of glass were' broken.

A remarkable phenomenon was witnessed at midnight. In the bright, ruddy light it was observed that boiling lava, glowing with fierce heat, suddenly filled the crater, and, over-flowing, pour*. fi d down the sides of the mountain. Previously the lava had flowed down the northern slopes of Ngauruhoc, towards bi\t so immense was the quantity ejected that the southern slopes towards Ruapehu were also covered with molten material. The southern face of the mountain has hitherto been free from volcanic deposit. The shots were constantly renewed all through the night, some of them reaching an estimated height of 3000 ft, o> 4000 ft, the flight of red-hot boulders through the air being clearly discernibl# several miles away. There was bright moonlight on Saturday night, the first really bright night since Ngauruhoe sprang, into action on October 20, and the full spectacular effect of the eruptibn could be seen. It was a terrifying and truly awe-inspiring sight. Throughout Sunday night dense volumes of smoke and occasionally some solid material were being emitted from the crater, and to-day there was a continuance of the same conditions, with long-sustained reverberations mid earth shocks. With the exception of one brilliant shot early >n the evening, the volcano lias been moderately quiescent to-night. The summit is. again hidden by clouds.

When Ngauruhoe first, showed siuns of violent activity the peak and a large portion of Mount Toiigariro were, white with snow. The snow has now disappeared. The position of the crater is being proved slightly to the northward. Erosion of the crater in now taking place, and the symmetrical contour of the peak is being altered. Travellers from, many scattered districts a« far as Taihape report appreciable subterranean rumblings. It ij stated that when fry. ing-pan flat, near Rotorua, broke into violent thermal activity early in the present year Ngauruhoe became very quiet, and the Bfnoke and the steam which were to be seen issuing from the crater at normal times became less in volume. Since the mountain became active a fortnight ago, in addition to the material being ejected from the main crater, steam has been observed issuing from blow-holes about halfway down the southern slopes.

NATURAL SAFETY-VALVE.

FIRST FLOW FOR 48 YEARS.

The present eruption of Ngauruhoe was stated by the Professor A. P. W. Thomas, who, until his retirement from active work, was professor of geology at the Auckland University College, to represent the first instance of an over-flow of molten matter from the crater since 1869 Professor Thomas made a survey of the Tongariro volcanic system in 1887, shortly after the Tarawera eruption, and then examined a stream of lava which had poured down the north side of Ngauruhoe in the 1800 outbreak into the south crater of Tongariro. A sample of the solidified flow of last week which was brought to Auckland by the Herald representative who slept oil the mountain on Friday night, was pronounced by Professor Thomas to be of the same general character as the lava of the 186!) overflow.

Ngauruhoe is described by 'Professor Thomas as the dominant vent of the Tongariro volcanic system, and uie only cone of the series from which lava has been ejected within the memory of liv ing man. At various periods in the last 30 years the volcano has displayed activity to the extent of emitting steam, clonds and showers of stones, and changes have been reported from time to time in the outline of the top of the cone. These, however, until now, liave 1 been the only manifestations of the power of the mighty subterranean forces. Tongariro has not been known to show activity during the historic period. The only active points in the group for soma time past, other than Ngaumhoe itself, have been: (1) The Red Crater to the north-east of the mountain, which had ejected stones shortly before Professor Thomas's inspection 'in 1887, and has since shown similar activity at intervals: (2) the steaming pools of'Te Mori, stiil further to the north-east; ami (3) Ketetahi. a similar pool on the northern side of the group. As to the deductions to be made from the present eruption, Professor Thomas remarked that while it is rash to make any prediction as to the probable action of any volcano, still, while Ngatiruhoe shows a fairly free vent, as at'presont, it mil v reasonably be regarded as a kind of safety-valve to the pent-up subterranean forces in its neighborhood. The present startling phenomena imply the existence of pent-up forces, and is reassuring to know that a vent is provided for them, inasmuch as they are the less likely to accumulate such pressure as would lead to an explosion in some other direat,ion