Auckland's Rangitoto Island. Photo: 123RF
Scientists have visited Spain's Canary Islands to better prepare Auckland for a volcanic eruption.
An 85-day eruption in La Palma in 2021 saw 160-million cubic metres of lava bury hundreds of homes.
GNS Science said while the chances of a major eruption in New Zealand were low, if an eruption occurred in Auckland, lava could flow for hundreds of metres to several kilometres.
Volcanologist Dr Geoff Kilgour said a Natural Hazards Commission funded trip he recently led in La Palma gave researchers a better understanding of how lava would impact Auckland.
"There are very few lava-producing eruptions that have occurred in built-up areas like Auckland, which is why La Palma is such a good example of how lava interacts with buildings and infrastructure."
"We spoke to Canarians who lost their homes and have had to relocate, and others whose health is suffering because they continue to live in damaged homes they can't afford to repair."
He said observing how lava ignited fires in La Palma, would also help predict Auckland's risk from lava fires.
"We expect fires to be a big issue in Auckland, where we have many more timber frame buildings, and our volcanoes produce similarly hot and fluid lava."
He said Auckland would likely face similar engineering challenges to La Palma rebuilding critical infrastructure after an eruption.
"Layers of cooling, but still very hot lava means nothing heat-sensitive can be built directly on or below ground. Some of the solutions [in La Palma] had to be quite savvy, including going back to old Roman techniques for building roads involving limestone, which hardens with heat."
Accurate post-eruption analysis was crucial for safety advice and insurance payouts, he said, and initial damage assessments made from satellite-based images did not provide enough detail.
"Although it's convenient for getting a rough idea of the scale of total destruction, it doesn't pick up on smaller and more nuanced damage.
"We see benefits from on-the-ground analysis happening as soon as possible post-eruption, so that people can begin to rebuild their lives."
Kilgour said he was currently working on applying his findings to an Auckland context.
The National Emergency Management Agency's 'Get Ready' website has extensive information on actions you can take before, during, and after volcanic activity.
