Russell Blackstock

Russell Blackstock is a senior reporter at the Herald on Sunday.

Sunday Insight: Volatile volcanoes

Steam billows from vents at the summit of Mt Tongariro. Photo / Alan Gibson
Steam billows from vents at the summit of Mt Tongariro. Photo / Alan Gibson

Our volcanoes are more unpredictable than we ever realised, new research reveals. Ruapehu, White Island, Tongariro, Auckland . . . the whole North Island is a tin lid clipped atop a pressure cooker, as shown by this week's eruptions. So why are we still so complacent - and why is the property around Auckland's volcanic cones still the most valuable in the country?

Kerry Wakelin friend woke her from her sleep. That was unusual. Rupert, a Jack Russell-cross, doesn't generally ask to be taken for midnight walks along the track near the web designer's apartment, tucked at the foot of Mt Tongariro.

"The next thing, the sky lit up like a big flash of lightning followed by a huge grumbling noise," Wakelin says. "Then I saw a large black cloud appear near the mountain. I assumed it was a bad storm, so went in and went straight back to bed."

What she had unwitting witnessed was the volcano erupting for the first time in 115 years. It rumbled into life at 11.50pm on Monday, throwing ash and rock a kilometre into the air, sparking a potential threat warning for Central North Island regions.

"I didn't know until the morning it was an eruption I had seen," she explains. "And then I realised Rupert had woken me up and wanted out because he must have felt the tremors."

Wakelin, 47, had worked at the Whakapapa ski field during the major eruptions on Mt Ruapehu in the mid-1990s and insists she isn't fazed by the simmering volcano on
her doorstep. "The Ruapehu situation was scary but the Tongariro eruption was more like a fart. It was nothing, really."

Nothing, really. Nothing, when hectares of farmland are coated in ash. Nothing, when boulders smash through the roof, water tank and beds in Ketetahi Springs Hut. Nothing,
when flights in and out of the east side of the North Island are shut down. Maybe it's because we're such a famously stoic people, but would the people of any other nation describe such an eruption as "nothing, really"?

"Stoic" is the generous description. A more accurate one might be "complacent".

New research by Devora (Determining Volcanic Risk in Auckland), a multi-agency project to determine Auckland's volcanic risk, has discovered previously unknown levels of volatility in this country's volcanoes. This heightened risk, disclosed by Devora project team leaders to the Herald on Sunday, should be a wake-up call to Aucklanders, in particular.

Next month, a Civil Defence exercise will try to shock New Zealand into action by enlisting a million of us-at home, work and school-to participate in the world's first nationwide earthquake drill.

Civil Defence national information boss Vince Cholewa observes: "It's the kids we really have to get through to from an early age, so awareness and preparation for a major national disaster comes almost second nature and is passed to future generations."

New Zealand's varied landscape and its towering mountain peaks owe a lot to the tectonic uplift of land and volcanic eruptions caused by the Pacific and Indo-Australian Plates clashing beneath the Earth's surface, which has left parts of the country seismically active.

The world's most dramatic volcanic eruption in 5000 years occurred here about 200AD. The Taupo eruption devastated much of the central North Island, emptying Lake Taupo in the process.

Since Maori first settled here, they have seen volcanoes Tarawera, Rangitoto, Taranaki, Tongariro, Ngauruhoe, Ruapehu and White Island intermittently and unpredictably spew out fountains of hot ash or lava.

The once-dazzling pink and white terraces on the shores of Lake Rotomahana were New Zealand's greatest national treasure.

They were cherished by Maori and known far and wide as the eighth natural wonder of the world. Then, during an immense volcanic eruption in 1886, they disappeared. They now lie below the lake.

Mt Ruapehu erupted most recently in 1995 and 1996. Mud flowed through the Whakapapa ski field and the slopes of the mountain were coated with volcanic ash.

Auckland, a city of 1.4 million people, sits uneasily atop more than 50 volcanic cones.

We have always been told about the danger of earthquakes - but the volcanoes, they told us, were dormant. Well, this week one of them erupted ...

New, unpublished scientific research disclosed to the Herald on Sunday shows there has been a lot more volcanic activity in the past than first thought, meaning the country's volcanoes, especially around Auckland, could be more unpredictable than previously believed.

A volcanic eruption in Auckland in the next 50 years has about a 4 per cent likelihood, although "considerable uncertainty surrounds this figure", according to the Ministry of Civil Defence and Emergency Management.

Last year, four new volcanic craters were discovered underneath South Auckland by Geomarine Research, bringing the total number of volcanoes in the Auckland volcanic field to 55. The most prominent of the new finds is a 300m diameter crater surrounded by a semicircular rim of volcanic ash in Boggust Park in Favona, Mangere. The other three craters are in Puhinui Reserve, Wiri.

Geomarine Research's Hugh Grenfell believes complacent Aucklanders should treat the sudden eruption at Tongariro as a wake-up call.

"There are a number of other places in the world with volcanic fields, the difference is none has a city the size of Auckland built on them," the geologist says.

A main focus for scientists and researchers from the seven-year Devora project has been boring into sediment layers deep under volcanic crater lakes such as Lake Pupuke at Takapuna to determine more accurate levels of activity over time.

The results have been surprising. Previously undiscovered layers of ash found under the lakes from other volcanoes further south, including Taupo, Okataina and Tongariro, suggest that New Zealand has undergone more volcanic activity than first believed.

Dr Jan Lindsay, one of the country's leading volcanologists, is a leader of Devora.

She says tests on new layers of sediment show Auckland has undergone a lot more volcanic movement in the past 30,000 years than known before. This raises questions about the future volatility of all Auckland's volcanoes.

Worse case scenarios for the city include Rangitoto Island blowing apart, vapourising
everything in its path, or cones the size of Mt Eden bursting out in Queen St, uprooting buildings and destroying infrastructure.

If magma was to travel 80km to the surface and hit sea water, the eruption would create a catastrophic explosion, says Lindsay. "There would be clouds of hot ash and steam. It would be a very significant event," she explains.

An eruption in the city centre could be just as devastating. "If the magma kept coming and there was enough of it, it could produce a scoria cone as big as Mt Wellington in the heart of the CBD."

Lindsay also reveals new findings showing Rangitoto is likely to have erupted more often than first thought.

"We used to think that a volcano wouldn't erupt twice but now we know that might not be the case. Imagine if a volcano the size of Rangitoto popped up in downtown Auckland? That could happen, because it has happened in the past.

"And who knows when the next one would be-it could be next week or in a thousand years. That is just the way it is."

Lindsay does stress that despite the large number of volcanoes in Auckland, she believes the field is currently stable and a greater threat to the city is likely to come from the fallout from a large eruption in the central North Island or elsewhere.

That is why volcanologists from around the world, including Dr Tom Wilson from GNS Science, descended on Tongariro this week.

"In Chile, I saw the damage volcanic ash can do from the eruption there last year. If the same thing was to happen in New Zealand it would be catastrophic," he says.

"Cities and towns would grind to a halt, waterways would be clogged up and the land that livestock feeds on would be so badly affected thousands of animals would die from starvation or poisoning."

If an eruption the size of this week's one occurred in Auckland, the chaos would be immense, says the city's Civil Defence boss Clive Manley.

"Depending on the time of day, up to half a million people would be evacuated to outside of a 5km exclusion zone," he explains.

"I would expect a 3km zone to be severely impacted by an event such as one in Tongariro. Ash would close the airport, roads would be shut, power and water supplies cut off and thousands of business affected."

It is estimated Auckland's GDP would drop by 47 per cent in the short term at least, costing the country billions of dollars.

"How long it would take to recover economically from something like that is anyone's guess," Manley says. He won't speculate at numbers of potential casualties but believes most deaths or injuries would likely be caused by people refusing to leave the area or their homes.

"History shows that this has been the case in a lot of major evacuations around the world.

"Hurricane Katrina in the United States a few years back was one of the best-managed evacuations ever, but there was still a lot of casualties from people who just wouldn't budge. And you can't force them."

Auckland University PhD student Bob Wang has his bags packed . His car at home in Epsom is loaded with emergency equipment, including food, water, torches, batteries and a tent. He is ready to meet members of his family at a prearranged spot for them to escape the city as quickly as possible following an unexpected volcanic eruption. He has prepared a DIY emergency plan to follow in case of a major event.

"I have taken a first-aid course and learned some survival techniques. I also have developed a habit of keeping my car topped up with petrol."

The 26-year-old is studying electrical engineering at the University of Auckland. He says people are all talk but no action and he is worried by their complacency.

He is so concerned about volcanoes going off he tried to form a survivalist group. He was disappointed there were no takers.

On internet blogs and forums, pockets of concerned citizens such as Wang swap survival tips and information about Auckland's volcanoes. But they are in the minority.

Wang's concern may seem excessive, but Civil Defence chief Manley reveals most of us err on the side of unpreparedness. Most Aucklanders feel too safe and therefore think it's not worth the bother of preparing for an eruption, he says.

Frustratingly, little has been learned fromthe deadly earthquake in Christchurch.

"Our latest research shows Aucklanders are the least prepared in the country. It is great they feel they live in a safe place but because of the number of volcanoes it is not wise to simply ignore planning what you would do if a natural catastrophic occurred.

"They seem to think they are in a place with plenty of resources and nothing will happen to them."

Manley adds: "There was a big spike in awareness after the big Christchurch earthquake but that has pegged back dramatically. People in Christchurch and Wellington are twice as well prepared as Aucklanders."

Auckland does not look like a city built on a volcano. The views and lush plant growth afforded by the volcanic cones make them some of the city's most lucrative real estate.

Real estate firms say people are even battling to buy in volcanic hot spots. Interest in areas such as Mt Eden, Epsom and Hobson has never been higher and people are still prepared to pay top dollar to be in the zones for the best grammar schools.

House values in Auckland are still soaring. Prices rose 3.1 per cent in the three months just gone, with an average sale price of $656,846. Values are up 6.3 per cent on an annual basis.

"People in Mt Eden and Mt Wellington are more concerned about the school fees erupting than they are about a volcano going off in the garden," says Michael Williams, regional manager for Barfoot &Thompson. "It is just not an issue and never has been. At recent auctions, people have been swinging from the rafters to get in and buy a house."

The truth is, New Zealand has volcanoes and quakes and storms and much more. They will always be with us. If you want to be entirely safe you are in the wrong country.

If we are going to build our houses atop a simmering pressure cooker, we can at least manage the risk.

In the event of an eruption, the Government's Get Ready, Get Thru website advises doing all the usual things like putting together an emergency kit and a household emergency plan. You should also have essential emergency items in your workplace and in your car.

And the nationwide ShakeOut drill, beginning at 9.26am on September 26, will give all New Zealanders a chance to test and ready themselves.

About 700,000 Kiwis the length and breadth of New Zealand have so far pledged their support through a campaign targeting schools and businesses - but more are welcome, says Civil Defence public information boss Cholewa.

"It is a worry when people's safety plan is based on not being prepared," Cholewa says. "It is perhaps even timely that the eruption happened in Tongariro and that no one was hurt or extensive damage done.

"It will perhaps remind people about the importance of being prepared through joining the Shake-Out event and getting up to a million people participating in practising 'Drop, Cover, Hold'.

"Some people in Auckland might think this is only relevant for earthquakes but you have to remember that any volcanic eruption in the Auckland region would be preceded by a series of quakes anyway."

The possibilities for carnage and chaos from our volatile volcanoes seem to be endless.

But back under the shadow of rumbling Mt Tongariro, dog-lover Wakelin isn't concerned about the danger brewing in her backyard.

"When I was caught up the Ruapehu eruption I was frightened and worried that something catastrophic was going to happen, and it didn't," she says. "Having been living close to the mountains for years I have learned to live with the situation and I'm pretty comfortable with it.

"I'll be back out on the tracks walking Rupert tonight, same as usual."

- Herald on Sunday

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