| New Zealand News | Friday July 20 2012 14:45
A swarm of small earthquakes under Mt Tongariro has prompted scientists to raise the volcano's alert level
Volcanologist Brad Scott says there is normally an average of two small quakes a year under the mountain.
But in the past week they've measured around 20.
He says that's prompted them to raise the alert level from zero to one - on a scale of one to five.
"Which puts it on par with both Ruapehu and White Island which have been on level one for a long, long time. So this is really just the first step on the ladder."
Mr Scott says there's no increase in public risk, including to people who want to walk the Tongariro Crossing.
It's believed there were ash eruptions from Tongariro between 1855 and 1897, as well as unconfirmed activity in 1926 and 1927.
Photo: NZ Herald