Rotorua Steam Eruption Occurred At “Hot Spot”

Press, Volume XCIX, Issue 29260, 19 July 1960, Page 17

Rotorua Steam Eruption Occurred At “Hot Spot”

“The Press” Special Service

AUCKLAND, July 18. The ground at the seat of the Poihipi road steam eruption had been getting hotter ever since a 100 ft bore had been drilled there and sealed off nearly 10 years ago, said the Government vulcanologist in Rotorua, Mr J. Healy. Nearly 100 ft of the Poihipi road, three miles north of Taupo, was destroyed about 1 a.m. last Friday. The Department of Scientific and Industrial Research had struck steam after drilling 100 ft near that point, said Mr Healy It had been sealed off. Although the spot had been “warm” before, it had become hotter ever since, he said. Steam getting nearer to the surface through the drill hole had caused the area to heat up. Most such eruptions were confined to thermal areas along fault lines. They were probably caused by additional heat flows under a cer-

tain point and steam pressure built up until it was great, enough to blow the rocks off the top.

Craters from such eruptions had been recorded at Whakarewarewa, Waiotapu and west of the Poihipi road explosion. The last such eruption in the district, however, had been the Tarawera eruption of Rotomahana. Mr Healy said he thought the danger of such eruptions in the centres of town and thermal districts such as Rotorua and Taupo was not great. “You can never tell, though,” he added. The eruption occurred On a dirt road—formerly the main highway to Taupo—well away from houses and more than a mile from the nearest discharging bore at Wairakei.

A wide crater which was filled with water on Sunday had formed just north of where the road crossed a small creek. The force of the explosion tore out half of a wooden bridge. Effect of Eruption

A one-acre plateau overlooking the crater was covered in upi to 2ft of pumice spoil. Rocks weighing up to half a ton were thrown more than 100 yards. One sheep was killed. Pine trees nearby were stripped of their branches.

Steam activity—which made it almost impossible to estimate the extent of the damage on Friday—has since died down considerably

The explosion blocked a short cut from Taupo to isolated villages north of Lake Taupo. However. no district was cut off.

The road was sealed off al points near the eruption. The Taupo County Council will decide this week on the future of the road.