David Whitley discovers that the usually placid waters of Lake Taupo are not what they seem
On New Zealand’s North Island, you’re never far from an active volcano or two. In a country that regularly shakes, rattles and explodes, it pays to have a passing interest in what’s happening underground. New Zealand is a nation of amateur seismologists and volcanologists, all acutely aware that something deadly could kick off at any time.
New Zealand lies on the Pacific Ring of fire; the Pacific and the Australasian tectonic plates grind into each other just off the east coast of the North Island, before cutting through the South Island and forming the Southern Alps.
On the North Island, the earth bears more than a passing resemblance to an upset stomach after a fiery curry. Geothermal activity is rampant, particularly in the centre around Taupo and Rotorua. Steam rises out of vents in the ground, geysers shoot upwards and towering volcanoes dominate the landscapes they oversee. Looking across Lake Taupo from the amiable city that shares the same name, the triple threat of Mt Tongariro, Ngauruhoe (its striking conical vent) and Mt Ruapehu loom. The ash and steam emerging from the side of Tongariro hint that the two minor eruptions of 2012 weren’t an end point.
But these aren’t the volcanoes to truly fear. The real monster is the serene lake in front. Lake Taupo is roughly the size of Singapore. But it’s not just a lake – it’s a caldera. If it goes up again, there’s a strong chance that most of the North Island will be destroyed.
A few kilometres north of Taupo is the Volcanic Activity Centre, a strong candidate for the North Island’s most underrated visitor attraction. It contains an earthquake simulator, shows videos of Ruapehu’s eruptions in 1995 and 1996, and has brilliantly lit-up 3D map dioramas showing where the pressure points are.
Computer screens linked to Geonet, the scientific body that monitors potential geological hazards in New Zealand, show the most recent earthquakes to strike the country. What’s alarming is how many there are – by my count, there had been at least three by midday on the morning I visited. Small ones, hardly felt, but still.
A rule of thumb chart on the wall is even more terrifying. It seems New Zealand can expect one earthquake between 4.0 and 4.9 on the Richter scale per day, two between 6.0 and 6.9 every year, and one between 7.0 and 7.9 every two-and-a-half years. Gulp.
But it’s the tale of Taupo’s eruption that really sends the shudders down the spine. An illustration of comparative ash clouds shows the extent of it. The biggest eruption in my lifetime was that of Mount Pinatubo in the Philippines, back in 1991. That sent out 10 cubic kilometres of material, changed weather patterns in Asia and had devastating consequences.
In 1883, Krakatoa in Indonesia went off, sending out 18 cubic kilometres of rock and ash from beneath the earth’s surface. It darkened the earth’s skies for years afterwards and global temperatures dropped by over a degree in the following twelve months.
The Taupo eruption sent out 100 cubic kilometres of gunk that now lines much of New Zealand’s North Island. ONE HUNDRED. That’s ten Pinatubos. Or five-and-a-half Krakatoas. Either way, it’s a phenomenal amount.
The scary thing is when it happened. This wasn’t a prehistoric event – Taupo is believed to have erupted in 186AD. Contemporary Chinese reports documented blood-red skies, not knowing where they came from. In a British context, that’s after Hadrian’s Wall was built. It was, simply put, the most violent volcanic eruption of the last 5,000 years.
And the forces that caused it lie, occasionally restless, under that gorgeous lake.
Fancy your chances, punk?