James Muirhead

Auckland is one of those places that's low risk.

But if you look at the boundaries of where that sits, Auckland is situated less than 100 kilometres away from a medium risk zone.

And the question that we have is if we collect more data on understanding earthquake history, is it going to shift the position of that zone?

And therefore, have we made the correct decision to basically rule out Auckland from these earthquake-borne building rules?

I'm not saying that if we do this research that it actually will shift Auckland into that.

It could actually find that it's even more safe.

But what we really want to do is make sure that we're making decisions based on empirical scientific data rather than our best hopes.

It couldn't be of the magnitude of Kaikōura.

Fault lines along that region have the potential to reach magnitudes of 8.

So the Mangatangi Fault was one of the larger faults that we've identified with a magnitude of 6.8.

And the important thing is to realise is actually

The amount of shaking from an earthquake like that will be 10 times less than the Kaikōrō earthquake, though the Kaikōrō earthquake is a very large earthquake when you think of global standards.

The Christchurch earthquake, just as an example, was a magnitude 6.3, so that's actually lower than the maximum magnitude for the Mangatangi Fault,

But I will add that that earthquake was very shallow and it occurred immediately below the city.

So an earthquake on the Mangatangi Fault would not have that impact, but it could generate as much, if not more, energy during the event.

Yeah, we haven't looked into the tsunami modelling for that.

So there are fault lines that run off the coast around Auckland, and so they will displace water bodies in the Wairamata Harbour.

I'm not sure, and it would require modelling, that it would displace the sort of amount of water that you see for these really large tsunamis that have occurred in the past in places like Japan in 2010 and then Chile in 1960, if people are familiar with that.

That's going to be an ongoing question.

I think it's unlikely that an earthquake would, for instance, trigger a volcanic eruption in a place like Auckland.