Auckland fireworks
Posted 6 December 2007 // Simon Nathan
Motukorea, Auckland’s most intact volcano
Our new entry on the Auckland region is now on Te Ara – a big welcome to the City of Volcanoes. To a scientist, Auckland is an exciting place, with cones and lake-filled craters dominating the landscape. There are about 50 vents within 20 kilometres of the city. On average there has been an eruption every 2,500 years for the last 50,000 years.
Rangitoto, in the centre of Auckland Harbour, erupted about 1400 AD. We don’t know how long the eruption lasted – perhaps it was weeks or months. It must have been a spectacular fireworks display, visible all around the Auckland region. There was probably a pall of ash over much of the area now occupied by the city, and an acrid, sulfurous smell. The first Polynesian settlers had only arrived about 100 years earlier. We do know that people saw the eruption because their footprints are preserved in ash on nearby Motutapu Island. Isn’t it incredible that one day we may be able to test these for DNA, and perhaps identify their descendants!
While the chance of an eruption in a human lifetime is quite low, the impact on New Zealand’s largest city would be enormous. Auckland has a contingency plan, and local scientists and planners have formed the ‘It’s our Volcano’ group to consider the likely warning signals and effects of an eruption..
But there is a positive side. Past eruptions are responsible for the fertile soils of South Auckland – one of the best market gardening areas in New Zealand.
