Risk

Volcano risk - video transcript

Kate Hawkesby:
In breaking news this morning the increased volcanic activity near Rangitoto Island leads to a state of emergency.

Tens of thousands of residents on Auckland's North Shore may have to be evacuated.

Scientists warn that after weeks of ominous signs a volcanic eruption may be about to start.

Melissa Stokes has the latest.

Melissa Stokes:
Auckland residents have been on alert for months, hoping this day would never come, but scientists say the warning signs have been there.

The Auckland Council's measuring equipment has been recording clusters of earthquakes. The quakes have been too small to be felt, but scientists say they may signal the start of a volcanic eruption.

So now Auckland is on a level 2 alert after another swarm of shallow earthquakes hit the city at 1:35 this morning.

Woman:
The earthquakes kept coming; they were every half an hour or so.

Man:
I've never felt anything quite like this it was pretty scary.

Man:
Um. Not too worried.

Melissa Stokes:
Only minor damage has been reported from the tremors but for scientists the issue is not the earthquakes themselves, but what effect they could be having underneath the city.

Dr. Hamish Campbell:
This cluster of earthquakes is shallower than we've been seeing in the last few weeks. Quite clearly, the magma is rising, and may be about 30 kilometres beneath eastern Auckland. An eruption is probably imminent. We would say that, ah, it may erupt within 8 to 12 hours.

Male Voice:
Can you give us any specifics as to where this eruption might happen?

Dr. Hamish Campbell:
North Head and Mission Bay. In the central harbour region basically.

Male Voice:
That's in the middle of the city. How big an eruption would this be?

Dr. Hamish Campbell:
Well we don't really know. But, from everything that we do know, when this kind of magma hits water, it is highly explosive. And so we are expecting something pretty dramatic.

Kate Hawkesby:
It's been a momentous and terrifying day for Auckland. After lying dormant for nearly 600 years the city's volcanic field is coming to life.

Ironically it's an absolutely stunning evening here in Auckland; the kind of evening when everyone would normally be heading out to the beaches. Instead we are waiting. Not sure what to do next. Not sure if this volcanic threat is real or not.

Man:
Ah, we packed last night actually, when the earthquakes started. We're going over to my sister's place in Henderson. I guess it's probably reasonably safe over there.

Woman:
Trying not to panic. But I think this morning I just wanted to wake up and think it was all a bad dream, but unfortunately it's not.

Melissa Stokes:
By 8 o'clock this morning the roads out of the evacuation zone were grid-locked.

Man:
It's bloody ridiculous. We're supposed to be fleeing for our lives, and the traffic hasn't moved for 15 minutes.

Melissa Stokes:
Despite instructions from civil defence authorities, many people outside the evacuation zone joined the exodus, increasing congestion.

Roger Carson:
We're asking residents outside the red zone to stay in their homes until further notice.

Melissa Stokes:
Soldiers from Papakura military camp joined forces with civil defence staff and police, going door-to-door to make sure no one had been left behind. They also patrolled shopping centres to prevent looting.

By mid-afternoon the evacuated suburbs were ghost towns, and the normally congested roads were empty.

Throughout the afternoon the earthquakes which set off the evacuation gradually became less frequent, but tonight the city is still on a level 3 alert.

Kate Hawkesby:
With me in the studio now I have Colin Wilson professor of volcanology at Auckland University.

Professor Wilson, let't take the last point there first. We haven't felt any more earthquakes since early this afternoon, could it be that the threat is receding?

Professor Wilson:
No, absolutely not, um, we see no sign in any of the signal's that we have, the earthquakes rising towards the surface, the deformation of the crust all suggest that an eruption is imminent.

Kate Hawkesby:
So, you don't think that the authorities have over-reacted with the mass evacuation?

Professor Wilson:
No. Um, the size and style of the eruption is very difficult to predict; it's very difficult to evacuate once the eruption has started. So evacuating in due time and due course is very sensible.

Kate Hawkesby:
We've just received reports of dead fish and discoloured water being seen by our helicopter crew flying over the harbour. Is that likely to be connected with all of this?

Professor Wilson:
Very much so. That's probably a sign that the magma, the molten rock is now pretty much at the surface.

Kate Hawkesby:
So assuming there is an eruption what are we likely to see?

Professor Wilson:
Ah, the very first phases is, um, can generate what is know as a surge, laterally moving cloud of ash and steam and that is the biggest risk form the initial part of the eruption. Er, as the magma meets the water; hot rock meets cold water - you get explosive eruptions.

Kate Hawkesby:
Can people escape from them?

Professor Wilson:
No.

Kate Hawkesby:
Like how fast do they travel?

Professor Wilson:
The ones that have been observed in historic eruptions can travel at up to 150 kilometres an hour. So once they've started appearing and started moving there is no escape from them.

Kate Hawkesby:
Professor Wilson, I'll just stop you there. We're going to go live now to our camera at Sky City.

Just a few moments ago this cloud of steam started to rise up out of the water between Mission Bay and North Head. Professor Wilson?

Professor Wilson:
The, the eruption has started then.

Kate Hawkesby:
For viewers outside Auckland, we've just felt a short...

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