Cherie Howie is a reporter for the Herald on Sunday.

One-in-five chance of another big shake

Doug Avery standing in his quake-damaged bedroom in Grassmere, near Seddon, yesterday. Photo / Tim Cuff
Doug Avery standing in his quake-damaged bedroom in Grassmere, near Seddon, yesterday. Photo / Tim Cuff

People in central New Zealand are living with a 20 per cent - one in five - chance of another magnitude six quake in the next week, a scientist says.

Residents in Marlborough and Wellington have been battered by a swarm of strong earthquakes in the past month, including three over magnitude six.

The largest - a 6.6 - hit southern Marlborough on Friday.

GNS duty seismologist Martin Reyners said last night there was a 7 per cent risk of another magnitude six quake in the 24 hours to 5pm today.

But over the next week, the chance of another big one remained at just over 20 per cent.

Percentages were based on modelling, but it was impossible to be absolutely sure, Reyners said, and quakes could increase or reduce stresses on nearby faults.

"We were down to a 2 per cent chance of a six before Friday."

Reyners said the quakes were occurring further south from Cook Strait on to the east coast of the South Island.

"This quake is clearly on the southern end of that [July 21 magnitude 6.5] fault. This is an area that has numerous faults."

The country had enjoyed an extended seismically quiet time before the 7.8 Fiordland quake in 2009, and could now be moving into an active period like that of the 1930s.

"I can't say for certain that's going to happen, but Cook Strait often has magnitude sixes. "It happened in Seddon in 1966 and in nearby Cape Campbell in 1977.

"In New Zealand we can expect a magnitude seven every 10 years and a magnitude six every year.

"I think we're starting to get back to normal levels."

Other quakes around the country since Friday were normal background seismic activity, he said.

"The message is that living in New Zealand means living with earthquakes, so everyone should be prepared."

Meanwhile, Seddon residents had their eyes on other odds last night.

Marie Flowerday owns the building that houses Seddon's Supervalue store, and watched as the repaired shop reopened about 5pm.

"People are rushing in to buy Lotto tickets," she said.

"They're having the best night they've had in ages."

She planned to join the queue of those hoping for a lucky break.

"I can't have any worse luck."

Damage report

• Five people needed hospital treatment for quake injuries, Nelson Marlborough District Health Board spokeswoman Katherine Rock said. Four received minor injuries, while a 62-year-old woman broke her back when she slipped on water from her damaged hot water cylinder. She was in a stable condition in Wairau Hospital yesterday.

• No injuries were reported in Wellington.

• Marlborough Lines managing director Ken Forrest said power had been restored to all customers, except those with quake-damaged power boxes or wiring, by 4pm yesterday. Almost 7000 from south of Blenheim lost power after the quake and all but 100 rural customers had their power back before nightfall.
• Power was restored to Wellington on Friday night.

• People in Ward are being told to conserve water while the supply is repaired. Water has also been cut to several homes in Grassmere and Blind River Rd where significant repairs are needed.
• A Wellington City Council official said all major utilities and infrastructure had been inspected and were operating as normal.

Commuters attempting to hitch-hike home after all train services were cancelled on August 16. Photo / Getty Images
Commuters attempting to hitch-hike home after all train services were cancelled on August 16. Photo / Getty Images

• Transport Agency spokesman Anthony Frith said State Highway 1 between Seddon and Kaikoura had re-opened by noon yesterday after cracks in the road were fixed and slips cleared. The rail link between Picton and Kaikoura is closed until at least today while track and tunnels are checked.
• In Wellington, trains and buses are running as normal, and all roads are open.

• Most houses in Seddon are damaged, and five are uninhabitable. Search and Rescue and fire service staff found damage in rural areas similar to Seddon.
• Wellington City Council spokesman Richard MacLean said a few city centre buildings had superficial damage. The nine-storey lift shaft attached to the James Smith carparking building is to be demolished this week, and nearby residents were evacuated. Civil Defence found accommodation for about 30 people.

- Herald on Sunday

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