Newspaper Article 1995 – Crater alert stays

Crater alert stays

NZPA   Wellington

Mount Ruapehu’s alert status remained at level four today on a scale of five, despite scientists saying this morning that volcanic activity had eased.

Level four indicates accelerated volcano unrest, large-scale eruption imminent.

Ruapehu District Council chief executive Cliff Houston, who chaired a meeting at the council’s civil defence headquarters in Taumarunui this morning, said that although communities in the district were not at risk, the alert status would remain at four.

The Institute of Geological and Nuclear Sciences (GNS) volcanology project leader, Dr Ian Nairn, said an eruption was recorded at 6.25am today but apart from that, “seismisity” overnight was lower than that recorded over the past week.

The mountain has been spewing mud, rocks, steam and ash with alarming frequency for more than a week now, and yesterday mudflows forced the closure of two highways.

Three skifields on the mountain were shut for three days on Sunday night.

Dr Nairn said visibility on the mountain was poor this morning, but seismologists were still working on its “dome”.

He said the scientists could not yet be sure if Crater Lake was empty but he said much of the water has been lost and future eruptions are likely to throw up less and drier ash.

He said scientists were trying to have a close look at the crater lake today from a helicopter.

“As yet, we haven’t had a clear look at the lake because there is so much steam rising from it that it is not possible to get a clear view, but we suspect that a lot of water has been thrown out (by the eruptions).

“When the water is removed we will see much drier ash and probably less explosive events and we won’t see the enormous steam plume that has been above the mountain for days now,” Dr Nairn said.

Dr Nairn said recent volcanic activity on the mountain had been “very similar” to a major eruption in 1945.

“In that event the crater lake was thrown out and there was a lava dome in the crater.  That may be what is going to happen this year,” he said.

Civil Defence, meanwhile, has set up headquarters in Taumarunui at the Ruapehu District Council offices.

A no-go area in airspace over much of the central North Island was being reviewed, Civil Aviation Authority spokesman Martin Gosling said.

An area from Raetihi east to Gisborne and from Woodville north to Rotorua yesterday was closed up to 25,000ft because of the risk to aircraft engines from ash.

Ansett public relations manager John Cordery said today the restriction had affected Wellington-Rotorua and Wellington-Palmerston North flights.

“We are taking a different flight route between Wellington and Rotorua and have moved a little west in the flight between Palmerston North and Wellington’” Mr Cordery said.

All Air New Zealand Link flights were cancelled in and out of Hawke’s Bay Airport in Napier yesterday.

The airport is closed until further notice.

Day-time flights to and from Gisborne have resumed.

This was the display seen by 110 guests at the Chateau Tongariro at 6pm yesterday when Ruapehu’s second largest eruption occurred.
Pictures   Tim Whittaker

Fruit growers wait anxiously

Fruit growers in Hawke’s Bay are anxiously watching developments on Mount Ruapehu and are hoping a full-scale eruption will not create problems for their crops.

Horticultural consultant Ross Wilson, from Agfirst, said today that the poor 1993-94 Hawke’s Bay crop was blamed in part on the effects on the weather from the Mount Pinatubo eruption in the Philippines.

“If the Ruapehu eruption produces the same cloud effects we could have problems,” he said.

Mr Wilson did not expect falling ash from Ruapehu to pose a barrier to pollination, unless it was severely acidic.

“If it is inert then it will not provide too much of a barrier.”

Mr Wilson said the long-term effects on the weather and particularly sunshine hours were the biggest threat the eruption posed.

HB switches to level four

The Hastings District Council and Napier City Council have switched up to a level four “scientific alert” because of the volcanic activity at Ruapehu.

The fifth level on the five-level scale would only be used only in the event of a large-scale eruption.

The Hastings District Council’s senior emergency officer Paul Hawke, said all councils within a 140km radius of Ruapehu had moved to level four at 10 o’clock yesterday.

Precautions involved were to make sure the council’s essential services such as water and sewerage were maintained, and to protect all sensitive equipment.

The fifth level would also take in the protection of people, animals and vehicles, and ensure instructions were issued to the public.

Mr Hawke said the main concern for the Hastings area was that of falling ash, especially as Hastings was predominantly downwind of Ruapehu.

He did not expect a great deal of ash to make it to Hastings itself but warned the silica component of the ash was abrasive and could scratch cars.

Mr Hawke said the council might have to remain at the present preparedness level for some time, as in 1945, when continuous eruptions kept civil defence organisations on alert for nine months.

Mud and rocks are thrown high out of the crater lake on Mount Ruapehu seconds before the spectacular plume of ash and steam. At right, the two lahars at the top of Whakapapa ski field can be seen.