Toxic clouds from a volcanic eruption in Auckland could travel twice as far as previously estimated, research by New Zealand’s Natural Hazards Commission Toka Tu Ake shows.

The analysis draws on observations from the Ubehebe Craters in California’s Death Valley, where there is evidence of the clouds, known as base surge, spreading 10km-15km from their vents.  

Lead researcher Gemechu Teferi says Death Valley is a volcanic zone similar to the one beneath Auckland, and the data indicates previous projections on base surges are “far too conservative”.

“This is at least two times farther than previous estimates of how far surges can travel, and we want to know if such distances are also possible in the Auckland volcanic field,” he said.  

Mr Teferi has visited 30 volcanoes across the Auckland field and chosen nine sites for further investigation.  

The project will analyse rocks for geological evidence of base surges, and computer modelling will be used to estimate the distance previous clouds travelled and to simulate future scenarios.  

NHC chief resilience officer Jo Horrocks says the work has “implications for how we plan for future eruptions” and will help councils, emergency responders and loss modellers.  

“Although unlikely, the impact of a volcanic eruption on Auckland is huge and base surges will be one of the biggest hazards,” she said.

“A more accurate estimate of how far these deadly clouds will travel can help councils with evacuation planning and insurers with estimating potential loses.”