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Not If, but when

First, the good news: the odds are that a volcanic eruption won’t occur in Auckland during your lifetime.

Look at the maths: about 50 volcanoes have been produced over about 200,000 years, one every 4,000 years on average. But, we don’t yet know when many of these occurred. Current research aims to show whether eruptions have clustered in time and trend to more or less frequent activity.

An eruption may or may not happen soon, but it will almost certainly happen. It’s not a case of if but when.

  • There is no way of knowing when it will happen.
  • The last eruption (Rangitoto) was by far the biggest.
  • If all that is not enough, consider this: Auckland’s volcanoes are powered by low viscosity basaltic magma, which rises through the crust quickly, at several kilometres per hour. So when the next eruption happens, whether it’s tomorrow or in 4000 years time, we won’t get much warning.
  • It’s not just our local volcanic field we have to worry about. Auckland could be affected by a volcano erupting outside the city, such as Taranaki or Ruapehu or worse still from one of the super volcanoes such as Taupo Volcano, just as easily as a local eruption. Over the past 12,000 years, ash has coated Auckland, on average, about once every 400 years. Ash is the volcanic hazard most likely to affect Aucklanders. It may seem harmless, but it can cause a lot of damage.

Herne Bay Seismogram Drum

You read a seismogram like you are reading these words; the earliest time is at the top left and then goes along the line to the end and then starts at the left of the next line. The top-left is therefore the oldest data and the bottom-right the most recent. All the seismograms shown here cover a 24-hour period.

Latest feed for Herne Bay Borehole courtesy of GeoNet.

GeoNet, Creative Commons 3

What do drums look like when there is activity?

Find out

Volcanic surveillance in New Zealand

Just in case you’re panicking, let’s end with some more good news: scientists carefully monitor all of New Zealand’'s volcanic activity, and Auckland Council has detailed contingency plans for any volcanic disaster.

  • Seismic monitoring

    Scientists are constantly monitoring the Auckland Volcanic Field. Read about the tools of their trade.

    Read more
  • The big picture

    Did you know that scientists can tell if the ground under New Zealand bulges by just a few centimetres?

    Read more
  • Volcano web cams

    GeoNet images updated every 15 minutes. Scientists use a variety of techniques to monitor New Zealand's volcanoes. Check out the feeds!

    Read more