Play it safe - live in Hamilton

16:00, Mar 11 2011

A clutch of middle-aged British men stand around a long, low table, gazing at the map laid out in front of them.

The rugged coastlines of two islands zig-zag down the page, punctured with the shadows of mountains, valleys and forests. Above, the date: 1840. The name of the new country: New Zealand.

"It is the fittest country in the world for colonisation," Edward Gibbon Wakefield declares to the gathered committee of the House of Commons. "The most beautiful country with the finest climate, and the most productive soil."

Perhaps what one of them should have added was: "Yes, but do we tell them about the earthquakes?"

For the thousands of early settlers who travelled for months across choppy seas in cramped conditions, the massive 1855 Wellington earthquake was a frightening welcome to an unknown land.

The infamous jolt almost sent some of them scarpering back across the water.


"I have many times sat down for a few minutes to consider whether or not I should go on with what I was doing or cut and run away from everything and New Zealand," bemoaned Marlborough farmer Frederick Trolove after his house and farm were all but destroyed by the earthquake and ensuing tsunami, which swept all his wool stocks off the choppy Kaikoura coast.

Earthquakes and tsunamis. Crazy weather patterns, storms and cyclones, rain, rain, and more rain. Oh, and did we mention the volcanoes?

Despite the geological information the New Zealand Company decided to withhold from potential settlers, the majority of those hardy souls stayed. Along with the Maori, who had already been thrashed by the elements for decades, they built up a colony of survivors.

Because there's no getting away from it – on the cusp of the volcano-rimmed South Pacific, smack-bang on top of the crevasse between two of the Earth's plates and above a series of ferocious wind channels, living in this country is not for the faint-hearted.

Former prime minister Sir Geoffrey Palmer summed it up best in 1990, when he said: "Sometimes it does us a power of good to remind ourselves that we live on two volcanic rocks where two tectonic plates meet, in a somewhat lonely stretch of windswept ocean just above the roaring forties. If you want drama – you've come to the right place."

But what happens if you love New Zealand, but you prefer calm to crisis? What if you'd rather sip your tea slowly than have it smashed out of your hand by the force of a tidal wave?

Move to Hamilton, GNS volcanologist Dr Graham Leonard suggests.

Nestled inland, Hamilton, population 130,000, is his pick for the most geologically sound city in New Zealand. It's tucked away from the coast – cancelling out any risk of tsunamis – and is a safe distance from any fault lines. If Mt Ruapehu erupts, the volcanic ash is likely to be blown across the island, and it's far enough away from Auckland's volcanic field to be considered safe.

Even if the Waikato River flooded, it's in a deep enough riverbed that the city is unlikely to be affected, he says.

But if we're talking specifically about volcanoes, Dr Leonard's area of research, there are a number of places in New Zealand you could consider yourself safe.

The whole of the South Island is pretty much clear, with New Zealand's prevailing westerly winds extremely unlikely to send any ash from a North Island eruption across the Cook Strait.

Unfortunately, if you live in the North Island, there's really no escape – especially if you live in the volcanic hotspots of the Central Plateau and Auckland.

If Mt Taranaki, Ruapehu, Tongariro or Ngauruhoe blew their top, clouds of ash would billow across the central and lower North Island, jamming up wastewater treatment plants, overheating air conditioning units and taking out telecommunications and air travel.

"It's not toxic, but it is disruptive. The biggest injuries caused during ashfalls is people falling off their roof trying to get the ash off," Dr Leonard says.

The real danger zones for lahars – avalanches of mud and rocks – is in the immediate vicinity of these volcanoes which are, luckily, rimmed by Egmont National Park and Tongariro National Park.

Trampers and skiers would have to keep an eye out, and there would be mass damage as lahars carved a path to the coast.

Contrary to every disaster movie you've ever seen, molten lava moves so slowly you could easily outwalk the sludge.

Lakes Taupo and Rotorua are part of a cluster of "super volcanoes" in the central North Island, known as caldera volcanoes.

The carnage if one of these blew again doesn't even bear thinking about – Lake Taupo used to be flat land until molten rock pulsed up from the ground, throwing 1000 cubic kilometres of debris for miles around and leaving a massive hole that eventually became the lake. Happily, there were only tuatara around to witness this one in 10,000 year event.

Sorry, Auckland, but precariously nestled on a field of 50 active volcanoes, you could be considered a ticking time bomb. An explosive mix of two types of volcano – maar craters and scoria cones – are peppered beneath the city.

Last one to explode was Rangitoto Island, about 600 years ago, so the chances of us seeing an eruption in our lifetime are very, very slim. "But you can't rule it out," Dr Leonard says.

The Bay of Islands is also a risk zone, with 30 slumbering volcanoes at the last count.

At this point, you could be thinking about packing up and making for the east coast, or Wellington, or maybe the South Island.

But wait, let's factor in the Ring of Fire – the hundreds of volcanoes that line the Pacific, pushed up by tectonic plate movements deep under the ocean.

If one of those blew, tsunamis would be likely to engulf the country. Live in a low-lying coastal area? Swamped.

And then, there's the earthquakes.

New Zealand straddles the Australian and Pacific plates, with the major fault line carving a path from the east of the North Island right down to Fiordland in the south, GNS seismologist Dr Mark Stirling explains. About 15,000 quakes are tracked a year, with 150 felt by humans.

But that's not all. Miles off the east coast, the Pacific plate is trying to dive under the Australian plate.

Down south, the Australian plate is trying to cosy up underneath the Pacific plate. If either of these "subduction faults" were to rupture, the results would be catastrophic.

In the North Island, a massive rumbling earthquake would be followed by a monster tsunami which would engulf Gisborne, the Hawkes Bay and Wellington, with waves of up to 30 metres washing about seven kilometres inland.

Wellington is already widely considered New Zealand's most hazardous city, with no less than four major surface faults in the region.

In its 2007 Hazardscape report, Civil Defence estimated a rupture of the Wellington fault would cause about 4000 casualties, up to 600 deaths (depending on the time of day), and more than $10 billion of damage. The fault produces a major earthquake every 500-800 years; it last ruptured about 400 years ago.

Nowhere in the South Island is quake-free, with the Alpine fault slashing through the west and minor faults zig-zagging through Central Otago, Queenstown, Dunedin and Christchurch.

All up, GNS has mapped about 530 fault lines in the country – not including the sneaky little lines, or the offshore plates.

If you wanted to avoid any shakes at all, your best bet would be moving to the small settlement of Kaitaia in Northland, according to Dr Stirling.

"That's about as far away as you can get on dry land from faults, and areas of seismicity."

Unfortunately though, Northland is at the mercy of New Zealand's biggest and most expensive natural hazards – the weather.

As a group of small islands in the roaring forties, weather patterns mean that we experience a lot of high-intensity rainfall.

Humid, tropical cyclones bear down from the north, lashing the top half of the North Island. And though any weather event from the north brings more rain, Niwa meteorologist Dr Mike Revell says nowhere in the country is safe from nasty mid-latitude storms, which can bring winds of up to 230kmh.

On average, there are about 10 of these a year.

"There's nowhere you could rule out the possibility of having something like that. They can affect us basically at any time of the year, they tend to peak in the winter but there's no guarantee they won't hit us in the summer either."

Insurance industry statistics show that between 1968 and 2004, weather-related hazards were responsible for 74 per cent of all claims.

The entire country is at risk of flooding, with rising rivers breaking banks and landslides carving destructive paths down hills – the environment ministry estimates that on average a major flood occurs every eight months.

Though you might be more sheltered somewhere like Nelson, you couldn't escape the rain, Dr Revell says.

And you might not get any wind if you lived in the Mackenzie Country, but you would have to deal with temperature extremes of up to a sweltering 35 degrees Celsius in summer and a bone-chilling -20C in winter.

"There's no place in New Zealand that's immune from weather systems – we get it everywhere."

The bad news is, in this country, you get it all everywhere. If it's not raining it's shaking, and if it's not exploding it's flooding.

On the upside, it's made us a nation of battlers, with a fiery spirit and do-it-yourself mentality that has won us kudos the world over.

So in the end, there's really only one variable left to consider.

How badly do you want to move to Hamilton?

The Dominion Post