Community Outlook: The Big One

The Big One

In late March, Alice Lake-Hammond from Alpine Fault Magnitude 8 (AF8), presented a public talk on what the impacts of a large Alpine Fault earthquake might look like in our region. This was well attended and was a very informative presentation. AF8 are hoping to present these once or twice a year, so if you missed it this time, I would highly recommend attending next time.

While we can’t predict earthquakes, scientific research indicates there is a 75% probability of an Alpine Fault earthquake occurring in the next 50 years, and there is a 4 out of 5 chance that it will be a magnitude 8+ event. This is likely to have major short and long-term impacts.

This is not meant to be alarmist, but we need to recognise the risk and ensure we are prepared for such an event.

So, what would it look like in our region, if a magnitude 8+ event were to occur along the Alpine Fault?
The map below predicts that we are in one of the safer areas, however that doesn’t mean we won’t be affected.

AF8 Roadshow Locations

For some perspective of what a magnitude 8+ earthquake is – consider that the 2010 Christchurch earthquakes were around magnitude 6.2-6.3. A magnitude 8 earthquake could be 500 times stronger! We would likely feel considerable shaking due to the energy emanating out along the path of the Alpine Fault. This shaking could continue for up to two minutes. There would likely be at least two magnitude 7 aftershocks.

Southland could experience some occurrences of liquefaction, particularly around Invercargill, land slides and service outages for example; electricity, water, roads, and communications. There would likely be a period of disruption to services lasting from 30 days to 6 months. Since the areas most impacted to the north would need the major response, we would be somewhat isolated. Many of our problems would not likely be addressed for a significant amount of time. Road outages in the north of the South Island would create obvious difficulties getting food and resource supplies to us in the south.

What can we do? Be prepared. Ensure we have the resilience to survive in isolation for a period of time. Make preparations around the home for such an event and ensure our families, neighbours, and friends have a plan to follow.

More detail can be found on the AF8 website:
Information about being prepared for an emergency can be found on the Get Ready website:
Local details can be found on the Emergency Management Southland website:

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