Latest quake causes more slips in Rotorua district

1.00pm

Further road slips are being reported in the Rotorua district today after an earthquake at about 3am, which was the latest in a swarm of shakes over the past few days.

The latest quake measured 4.4 on the Richter scale and had been felt around the Lake Rotoma and Lake Rotoiti areas as a sharp jolt followed by rolling tremors, Rotorua District Council spokesman Rex Moore said.

No new reports of serious property damage had come in to Rotorua District Council today, but health and building inspectors were continuing to respond to earlier damage reports.

So far five houses in the district had been found unfit to occupy, and damage to many others had been identified.

Institute of Geological and Nuclear Sciences duty seismologist Martin Reyners said more than 200 earthquakes had been recorded since Sunday afternoon, but probably only about a dozen of those would have been felt by people.

They were getting fewer and farther between but every now and then there was a larger earthquake, such as the one this morning, he said.

But that shake had 30 times less energy than the largest of the earthquakes on Sunday.

It was thought possible the weight of the floodwaters could have triggered the earthquakes, Dr Reyners said.

Based on a quick calculation he thought something in the order of a billion tonnes of water had loaded up the crust in the flood area.

"This area where the earthquakes happened is tectonically stretching at the moment," he said.

"When you add a load, say water, it destabilises the region and brings forward earthquakes that may have happened some time in the future."

The earthquakes since Sunday probably represented pieces of the same fault breaking in sequence.

- NZPA