Shaken isles no closer to big one

20:56, Jul 08 2012

The North Island has been rocked by two large earthquakes in less than a week, but seismologists say the chance of "the big one" has not increased.

Tuesday's magnitude-7 quake and the 5.7 jolt on Saturday were not linked, even though they were on the same plate, GNS seismologist Lara Bland said.

"The only coincidence is that they're large, deep earthquakes – but in terms of whether one had been caused by the other, we don't see them connected in that way."

The latest rattles did not increase the chance of a devastating quake crippling the North Island. "We definitely don't look at them as making it more likely – the risk is still the same.

"As always, most of New Zealand could have an earthquake at any time, but that likelihood has not changed because of these two earthquakes."

Most of the country felt Tuesday night's quake, which struck 60 kilometres south of Opunake at a depth of 230km, and was followed by a 4.6 aftershock nine minutes later.


Saturday's shake, which struck at 12.50pm, was centred 10km south of Turangi at a depth of 90km. It was less severe, but still widely felt, Ms Bland said.

The quake would have been felt stronger further away from the epicentre because the energy from the tectonic plate dipping under the North Island followed the easiest path, which was to the east, she said.

Because of the depth of the quakes, the damage to homes and businesses was minimal.

The Earthquake Commission had received 339 claims, most from the lower North Island, as of Friday. A spokesman said most of the claims were of low value.

"Most of them are pretty minor – almost all are contents claims."

The Dominion Post