Evacuating Auckland when a volcano threatens eruption – Expert Reaction

Scientists have modelled how long it could take people to safely evacuate Auckland with advance warning of a volcano eruption.

They found the whole process could take up to 49 hours when the site of the new eruption is understood, and that people living in residential, suburban areas would require the longest evacuations.

The study is freely available here.

The SMC asked experts to comment on the research. 

Dr Adrian Pittari, Senior Lecturer, Earth and Environmental Sciences Team, Te Aka Mātuatua – School of Science, University of Waikato, comments:

“This study is a useful overview of the range of issues that would be faced should the risk of an eruption in Auckland be increased – particularly regarding our ability to make a decision to evacuate, then in the time required to evacuate an area. The volcanic risk in Auckland is real; so is the uncertainty in the location of the next vent within the metropolitan area. However, there are no signs of any imminent eruption or unrest in the deep subsurface, so the risk is no different to what it has been over the last few hundred years – which is currently low.

“Knowing more about what to expect and how to plan for a possible eruption is much better than the chaos that would ensue with less knowledge. This study offers a good plan for the authorities to work with to organise an evacuation. The suggested evacuation times are a good estimate, and evacuations would be successful in situations where rising magmas are detected early and there is enough time before they reach shallow levels in the crust to erupt. There are many variables to consider, some less controllable than others, and the study has considered these.

“One aspect to remember is that – whilst we don’t have any living memory of an eruption in Auckland – continued consideration and discussion amongst scientists, authorities and the public about the volcanic hazard in Auckland will ensure we are better prepared if and when an eruption occurs.”

Conflict of interest statement. I am not a member of DEVORA and am not directly collaborating on DEVORA-funded projects.

Professor Ben Kennedy, Professor of Physical Volcanology, College of Science, University of Canterbury, comments:

“This study is a key contribution to better preparing Auckland for a volcanic event, which will probably happen in the next few hundred years. The study explains that it will take around 50 hours to evacuate an area impacted by a potential volcanic eruption.

“The paper does well to explain that this will be less if 1) the population is prepared, 2) the eruption occurs in less populated areas, 3) roads are less congested, and 4) we know exactly where the eruption will be ahead of time. This last point is an important reminder to volcanologists that we need to refine techniques to work out how fast magma has risen in the past. At the moment estimated magma rise rates indicate timescales of less than a week, but with large uncertainties.

“Which means as volcanologists, we think we can give sufficient eruption warning, but we need to do more work to improve our confidence in our methods. Similarly, the study shows we should continue to work on improving how we monitor volcanoes, including preparing to more rapidly predict where an eruption may occur once we start seeing volcanic unrest.”

No conflict of interest declared.