While it is not going to break the nation, it will cause a lot of stress, Canterbury University science professor Thomas Wilson says.
Speaking to high country farmers at a field day in the Lees Valley, Thomas presented AF8 (Alpine Fault magnitude 8 earthquake), a programme of scientific modelling, coordinated response planning and community engagement designed to build collective resilience to the next Alpine Fault earthquake across the South Island.
“While we can’t predict when earthquakes will occur, we can prepare for them,” Thomas said.
Scientific research has shown that the South Island’s Alpine Fault has an unusually regular history of producing large earthquakes.
Over the past 8000 years, the Alpine Fault has ruptured 27 times, on average that’s every 300 years with the longest interval being 510 years and the shortest 140 years.
Of the last nine earthquakes, eight appear to have been greater than magnitude 8.
The last significant quake on the Alpine Fault was in 1717.
“The message is we are in high probability that the next severe earthquake on the Alpine Fault is likely to occur within the lifetime of most of us, or our children,” he said.
Research conducted by the University of Canterbury, University of Otago and GNS Science has assessed some of the environmental impacts that can be expected from the next earthquake of magnitude 8 or greater on the Alpine Fault.
Until now, there has been no comprehensive study of the impacts a rupture would have on people living in communities across the South Island, or on infrastructure.
AF8 is a collaboration between the six South Island Civil Defence Emergency Management (CDEM) groups and science, including research from six universities and Crown Research Institutes, emergency services, lifelines, iwi, health authorities and many other partner agencies.
Thomas says Alpine Fault science continues at pace with new research focusing on understanding the impacts and consequences of a future earthquake, as well as continuing to build knowledge of the fundamentals of the fault itself.
Marlborough Civil Defence emergency manager Brian Paton says the science-based scenario development to inform response planning reports a magnitude 8 quake causing major cascading consequences and secondary hazards, with significant human, environmental, infrastructure and economic impact.
“To develop a plan, we need to know how bad it can be,” Paton said.
“We need to have a coordinated response and we are working on a centralised South Island plan rather than each region devising its own plan.
“With a 400km-long fault line, this will be a logistical problem from one end to the other.”
There will be widespread secondary hazards such as landslides that will present immediate and long-term issues; likely isolation of areas for long periods of time and extended utility service outages such as electricity, water and communications.
“Your first responder is going to be your neighbour, not agency responders,” he said.
“We learnt a whole heap of lessons from the Kaikoura quake and how we can help people like you – high country farmers and your communities.
“We all have a part to play and it will be neighbours looking after neighbours in isolated rural areas.”
Paton urged farmers to have a large water supply for homes, a generator and a significant amount of fuel.
“Consider access tracks, know how you will cope if you are going to be on your own,” he said.
The framework of the AF8 programme is designed to bring all the learnings together and share them with emergency response agencies to improve coordination and collective response capability.
“The success of AF8’s approach has been thanks to the willingness of many people who have stepped up to give thought to the challenges that we will have to deal with,” he said.
“Now we need to educate communities as we encourage everyone to get prepared.”
The AF8 Roadshow kicks off this week with public talks and interactive school sessions aimed at equipping communities with the knowledge and interest to engage with the science behind an AF8 earthquake, its associated hazards and what it will mean for their community.
The roadshow takes in areas likely to be affected by AF8, starting in South Canterbury on March 23, venturing northwards to Kaikoura, across to the West Coast, and finishing in Invercargill on May 24.
To find a roadshow near you go to: https://af8.org.nz/af8-roadshow
