Dozens of significant aftershocks are forecast as unwelcome sequels to the magnitude 6.2 earthquake that damaged homes, cracked roads, toppled cliffs and left thousands without power.
The Wellington Anniversary Day quake, which struck shortly before 4pm yesterday, was centred about 15 kilometres east of the rural Tararua town of Eketahuna at a depth of about 33km.
It comes almost six months to the day after a 6.5 magnitude earthquake, centred near Seddon, set off a swarm of tremors that rocked the middle of the country for months.
The shaking from yesterday's quake was felt from Invercargill to Auckland but those in Manawatu, Wairarapa and Wellington bore the brunt of it.
There were no reports of death or serious injury to people, but it was thought about nine seals, including two pups, were crushed to death when a massive chunk of 162-metre-high Castle Rock, at Castlepoint, was shaken loose.
There have been no reports of damage in the Marlborough region.
People in Marlborough took to social media to immediately share their experiences of the quake, with almost 3400 people viewing a post on the Marlborough Express Facebook page after the tremors were felt.
Castlepoint Station manager and volunteer fire brigade chief Anders Crofoot said the boulder weighed about 20 tonnes and was the size of a small car. It sheared off a limestone face, south of The Gap beach, and bounced down a steep slope towards holidaymakers on the beach, he said.
A large slip near Mangaweka also turned the Rangitikei River milky-grey.
There were further reports of slips along the Pohangina River and at Anzac Cliffs on the Manawatu River.
Electricity was cut to about 5600 homes in Tararua, Manawatu and Taranaki but but lines company Powerco confirmed all were back on this morning.
Wairarapa Civil Defence emergency management controller Kevin Tunnell said there had been numerous reports of minor damage at homes across Masterton and the wider Wairarapa.
The quake was felt so strongly that Masterton Deputy Mayor Graham McClymont, who was playing golf in Eketahuna when it struck, feared Masterton would be "lying in a pile of rubble".
Near Masterton, Mauriceville residents John Hart and Karen Monks said their restored villa would need a second restoration to undo quake damage.
"The house is pretty much trashed. There's crockery everywhere, the fridge has emptied itself, we've got appliances on the floor, bookcases down, and there's quite a few cracks around the house."
Large cracks also forced the closure of the main road to the tiny Tararua town of Pongaroa.
A structural engineer will carry out a further examination on the three-storey residential Daniels Building in Masterton after a dangerous building declaration was issued yesterday, Tunnell said.
In Manawatu, there were reports of chimneys collapsing, cracks appearing in walls, and television sets falling over. A Palmerston North resident said concrete had sunk around their home.
Leeds St resident Maria Dalziel said her brick fence toppled "like a house of cards" when the shaking started. Inside, her collection of 100 antique glass bottles had all smashed.
Melanie Iosefa was in the central Palmerston North NZI insurance building when plaster fell on to a desk. The 15 to 20 workers in the building were forced to duck for cover on the floor but one woman sitting underneath received a blow to the head as she took cover under a table.
The earthquake forced KiwiRail to suspend all Tranz Metro train services across the region while it inspected the tracks.
Service would return to normal for the Wellington and Wairarapa commuter lines and the Capital Connection this morning.
KiwiRail chief executive Jim Quinn said track inspections had found only two areas of minor damage, north of Palmerston North and Masterton.
Heather Heatley and Naida Stephens were making their way home to Paraparaumu from the Trentham racecourse when the quake hit. Heatley said the buses arrived within 20 minutes to take them to Wellington station, and buses to Paraparaumu were not far away. "It was very quick service, we were really impressed."
The quake-prone Farmers building in Wellington's Cuba Mall was evacuated while inspectors checked for damage.
In Lower Hutt's Queensgate Mall, shoppers were left screaming and ducking for cover as items fell off shelves. Some stores closed afterwards.
Supermarkets in the Wellington region sustained only minor damage. Countdown closed two stores – one in Paraparaumu because it was within a mall that was closed and one in Feilding due to a power cut.
Stores in Lower Hutt, Otaki and Levin were also closed briefly while fallen stock was cleaned up.
Keith Marshall, duty manager at Pak 'n Save Masterton, said eggs and glass items fell over during the earthquake. The machinary that powers its refrigerators also automatically shut down.
"The store was reasonably full given the public holiday when the quake struck but customers just kept on shopping. But we do live on a fault line."
New World Masterton temporarily closed for about 15 minutes after the shake so staff could clean up about half a dozen broken bottles of wine and other stock that had fallen off shelves.
Inspectors would return the to Manawatu Gorge road this week to check the stability of the cliffs following the earthquake, he said.
GNS Science forecast there would be about two aftershocks of magnitude 5.0 to 5.9 and 23 aftershocks of magnitude 4.0 to 4.9 in the next week.
Seismologist Caroline Little said it would take time to establish which fault line triggered the earthquake.
- © Fairfax NZ News