Volcanic unrest on Mt Tongariro may last for several more months as the mountain enters an eruptive stage not seen for more than 100 years, GNS vulcanologists say.
The mountain, which erupted twice near Te Maari Craters in August and last month, has continued to discharge noticeable gas during the past week.
GNS vulcanologist Brad Scott said there was "a substantial possibility of further eruptions" during the next few months because of the recent unrest.
"Tongariro might quietly discharge steam most of the time, but occasionally have small eruptions with little or no warning," he said.
Dr Scott said there was a similar episode of activity in the 1890s.
GNS head vulcanologist Gill Jolly said it was difficult to accurately predict what would happen because scientists did not know a lot about the recent activity.
" . . . with active volcanoes nothing is black and white and our best assessments still have a lot of uncertainty."
Dr Jolly said there were no signs there would be bigger eruptions than had occurred in August.
There has been only minor seismic activity at Tongariro since November 21.
Gas may continue to be smelt downwind and be a minor irritant.
- The Dominion Post
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