A magnitude 5.7 earthquake has shaken Christchurch, nearly five years after a fatal tremor devastated parts of the central city. There are no reports of serious damage or injuries, but part of a Sumner cliff has fallen.
Geonet said the severe quake happened at 1.13pm today, its epicentre 15km east of Christchurch. It was followed by another moderate quake four minutes later and 10km north-east of the city. Aftershocks were continuing.
This video posted on YouTube shows part of the cliff falling:
The quake was felt throughout New Zealand - from Hawke's Bay to Invercargill, including Dunedin and Queenstown. It comes a week before the fifth anniversary of the deadly 6.3 magnitude quake in 2011 which killed 185 people on February 22.
Canterbury Earthquake Recovery Minister Gerry Brownlee confirmed that there were no reports of serious injuries. He said there appeared to be some damage to cliffs in the Port Hills, and Land Information New Zealand engineers were surveying the area.
There were also early reports of liquefaction in the east of Christchurch, but it was not extensive. Most areas which were susceptible to liquefaction and other damage had been cleared of housing after previous quakes, he said.
Engineering geologist Camilla Gibbons, who was part of the LINZ rapid response team, said there had been a "reasonable sized" cliff collapse at the far side of Sumner at Godley Head.
"We don't know how big it was yet, but it's sending up a huge cloud," she said. "There was also a cliff collapse at Wakefield Ave of a couple of hundred cubic metres. It's fallen down on what used to be the croquet pitches. Quite a bit has come down there but it's a lot less than in the last few quakes."
Mr Brownlee said it would be cold comfort for people who had already been through thousands of aftershocks in five years, but Sunday's strong quake was part of the predicted "decay curve" from the 2010 and 2011 tremors.
The minister said strengthening work done since those quakes meant people could be more confident about the way the built environment responded to a large shake.
The impact on Christchurch residents was more likely to be psychological rather than physical, Mr Brownlee said. "The uncertain bit is just what this does to individuals and how this shakes things up."
St John said it received a number of calls from people who had fallen over while running, but no reports of serious injuries.
District operations manager for Canterbury Dion Rosario said it had stood down its Emergency Operations Centre in Christchurch and ambulance services in the city and region were operating as normal.
"We encourage people to check on their neighbours, friends and families, especially those who are aged, ill or who live alone. If you have queries about non-urgent injuries or health issues, Healthline is available (0800 611 116) for free advice from trained registered nurses. For emergencies, call 111."
The Fire Service said there had been reports of liquefaction and a burst water mains in Pines Beach near Kaiapoi, and there was flooding and power lines down in New Brighton. However, it said there no big structural damage had been reported.
Emergency services said power had been lost to 450 customers between Burwood and Spencerville and at 100 homes in Akaroa. There was a police cordon at Scarborough Hill blocking access to the fallen cliff.
In Christchurch, shelves have fallen in homes, shops and libraries. Riccarton Mall and Northlands Mall were evacuated on Sunday afternoon.
A police spokesman said they have had no major reports of damage or injuries.
This video postedon YouTube shows the force of Sunday's quake:
'The cat took off'
Craig Mitchell was in Hornby when the 5.7 quake hit and said it "was like riding a wave".
Rosemary Revell was walking in Sommerfield when she thought she was suffering from vertigo. "I was nearly thrown off my feet."
Pam Hunt said the quake was "loud and long" in Rolleston.
Judi Thawley said the shake "sent my heart racing again". She said it was "long and loud, house shook but nothing fell.
"[I] feel sorry for the people in the east of Christchurch.
"Bob and Judy said it "brought back a lot of feelings".
"Even the two aftershocks were pretty good. Pictures fell and ornaments, the cat took off."
Rebuild Christchurch said in a Facebook post that people should check on elderly neighbours as soon as possible, stay away from cliffs, and document and photograph any damage to homes or possessions.
Over 15,000 quakes since Darfield
Sunday's big quake comes after more than 15,000 others, most of them too weak to be felt, in an aftershock sequence triggered by the 7.1 Darfield earthquake on September 4 in 2010.
That earthquake, which triggered the sequence that included the February 2011 deadly quake, was caused by strike-slip faulting, where two blocks within the crust of the Pacific Plate violently tore past each other, near the eastern foothills of the Southern Alps, at the western edge of the Canterbury Plains.
It set in motion activity in a web of faults beneath Canterbury - most of which are still probably unknown to scientists - that has carried on with nearly 1000 recorded quakes in the past 12 months.
- NZME, NZ Herald and ODT
