The general location of the offshore part of the Hikurangi subduction zone.
The general location of the offshore part of the Hikurangi subduction zone.
A seismologist has warned that New Zealand needs to be prepared for the potential of a massive earthquake, even if there’s no way to know when that may happen.
Earlier this week, the Resilience to Nature’s Challenges National Science Challenge was hosted at Te Papa, including a talk about the threats posed to the country by major natural disasters.
That included a focus on our largest fault – the Hikurangi Subduction Zone. During a session on catastrophic risk, the National Emergency Management Agency (Nema) detailed its work over the past 18 months, using a 9.1 Hikurangi earthquake and tsunami as its “planning scenario” for the “worst of the worst”.
If that earthquake were to hit, and assuming 70 per cent of people were able to evacuate, more than 22,000 would die – mostly in the tsunami – and nearly 26,000 more would be injured.
About 400,000 people would be displaced and 30,000 homes destroyed or damaged from the tsunami alone.
GNS Science seismologist Bill Fry was part of that panel. He told The Front Page the point of the planning wasn’t to create panic, but that we must plan and test systems to ensure we limit damage if something like this was to happen.
“By understanding how likely these things are, what they might look like when they happen, and then using that information to forecast impacts, we can test those systems that can improve our outcomes if it happens in our lifetimes,” Fry said.
A screenshot of a GNS Science model of an 8.9 magnitude Hikurangi earthquake. Image / GNS Science
He said that looking at 20 years of seismic activity in New Zealand, the country “always has the potential for a big earthquake and tsunami” that we must be prepared for.
“There’s never going to be a situation where we go through time we say, ‘okay, all the earthquakes are done, I’m finished with that, move on to something else’. And it’s this realisation that leads us to do things like testing the response systems or to even develop new tools to help us respond, things like tsunami early warning, being able to to look at waves, monitor tsunami waves before they arrive to our shores.”
GNS Science seismologist Matt Gerstenberger told The Front Page we can also use this information to plan for the long-term.
“You look at the potential earthquakes that could occur, the impacts that those could have, and that allows kind of long-term planning for things related to building code and different... urban planning-type settings.”
While we can plan and test our response to an earthquake or tsunami, Fry said we won’t ever be able to predict when the next big one will happen.
“The National Seismic Hazard Model is a model that we use to give probabilistic estimates of shaking that we might see in the next 50 or 100 years in New Zealand... Probabilities are likelihoods that shaking might occur in a particular location.”
Listen to the full episode to hear more about how experts are preparing for a natural disaster, and how worried they are about our national disaster threats.
The Front Page is a daily news podcast from the New Zealand Herald, available to listen to every weekday from 5am. The podcast is presented by Chelsea Daniels, an Auckland-based journalist with a background in world news and crime/justice reporting who joined NZME in 2016.
