Saturday, March 08, 2008
Experts inform government to expect a large volcanic eruption very soon!
But authorities are testing their readiness for a major eruption with a simulation exercise next week.
Exercise Ruaumoko will put evacuation, public information and emergency procedures to the test.
"It’s the first large-scale test of our plans," says emergency management group controller Harry O’Rourke.
"Nobody’s tried to do an evacuation of 200,000 or more people from Auckland, which is what we’re trying to do on paper."
The public are not involved in the practice run, but small focus groups will follow the scenario and give feedback on how they might respond.
The exercise scenario includes minor ground tremors followed by bigger shakes and finally a full-blown explosion.
Experts say there’s no way to tell where the next eruption will blow but it’s likely to be a new vent, not an existing volcano.
"There’s no real trend in terms of location or size," says Auckland Regional Council hazard manager Jane Olsen.
"It could appear anywhere within the volcanic field."
The first warning will come from Auckland’s seismic monitoring network, which picks up the small tremors caused by magma surging upwards from 100km underground.
It could take days or weeks to erupt, causing stronger earthquakes as it breaks through harder rock near the surface.
The most recent eruption 600 years ago created the largest volcano in the Auckland field, Rangitoto.
When the next one blows it’s likely to leave a devastation zone of 3km.
Most damaging will be base surges of gas and ash travelling along the ground at 100kmh.
"They’re extremely destructive but unlikely to travel too far from the vent," Ms Olsen says.
A 5km radius around the explosion would be evacuated, with up to 220,000 residents and almost as many employees forced to leave.
Police inspector Mark Hall says it would be hugely difficult.
"Auckland has enough problems as it is with roading infrastructure, without adding a mass evacuation."
Mr Hall says most people would be told to head south, because an Auckland eruption could block essential services to Northland.
Updates for the exercise can be read on www.exerciseruaumoko.co.nz.