Auckland's next volcanic eruption

The Auckland region has a volcanic eruption like this every 5000 years on average. Computer-created image / Brandspank.com

When Auckland's volcanic field next erupts it will look something like this. The picture is the creation of scientists and animators for Volcanoes, a new permanent exhibition at Auckland Museum.

Scientists who worked on the exhibition say an eruption is likely to come from a new volcano, rather than a known one such as Rangitoto.

It will be at a random location, as the molten rock finds the easiest route to the surface.

The exhibition, which opens today, may be fictional, but scientists say an eruption in Auckland is a matter of when, not if.

The good news: that is not likely to be any time soon. Auckland has a big volcanic eruption every 5000 years on average and the last one was Rangitoto, about 600 years ago.

Most people in the region will have to be evacuated but monitors will give a warning of "days to weeks" before the eruption, says Auckland University's head of geology, Ian Smith, who was involved in the early stages of the display.

The highlight of the exhibition is the chance to witness an eruption in the harbour from the lounge of a fictitious home in St Heliers.

The six-minute sequence has the lounge's television displaying "breaking news" while through the window smoke begins to rise from the harbour. Lights flash, the house shakes and the broadcast dies as the eruption sends debris kilometres into the sky.

Shock waves from an eruption will break windows and flatten buildings, fiery fountains of lava will set structures and trees ablaze, and base surges - a ground-hugging, deadly mixture of steam and solid particles - will envelop everything within a 5km radius. All that on Day One.

Yesterday residents of St Heliers thought the display a little too close to home. However, Sue Wilson said the exhibition would be useful. "If anything does happen we should be ready for it."