As thousands of shocked people wandered the rubble-strewn streets of Christchurch after today's devastating and deadly earthquake, emergency workers were searching for survivors. The cathedral crumbles in the Christchurch quake. Credit:Stuff.co.nz The 6.3 magnitude quake - classed by experts as an aftershock to last September's 7.1 quake - struck at 12.51pm (10.51am AEDT). The tremor brought down buildings on two buses, fractured gas and water mains, started fires, and badly damaged phone networks. Since then there have been a series of aftershocks, the strongest at 5.7. Do you know more? Text 0424 SMS SMH (+61 424 767 764), email us at scoop@smh.com.au or direct message on Twitter @smh_news

Christchurch mayor Bob Parker said: "There are people fighting for their lives at the moment but there are also people fighting for them. "We're in the middle of an extremely serious situation. We're preparing ourselves for what I think will be a really sad, bleak day for our city but be reassured: everybody is doing what they can." Mr Parker said people were still trapped in cars and buildings, with some being able to phone to say they were trapped. Local media reported a backpacker being killed in a van. Labor leader Phil Goff said he knew one person was killed in the collapsed Pyne Gould Corp building, where the dramatic rescue of a woman clinging to the roof was televised as scores remained trapped inside. The top floor of The Press’s building in Cathedral Square was destroyed and some staff still remained trapped in it, a reporter at the newspaper told smh.com.au. It is not known how many people were trapped, although earlier reports on TV3 said five employees were waiting to be rescued.

There are people fighting for their lives at the moment but there are also people fighting for them. We're in the middle of an extremely serious situation. We're preparing ourselves for what I think will be a really sad, bleak day for our city but be reassured: everybody is doing what they can The Ministry of Civil Defence said Christchurch Hospital had more than 40 injured people and expected the numbers to rise. There were also reports that "significant hotels" had collapsed and that two suburbs were beyond repair as the exodus from the city began. A state of emergency has been declared, New Zealand's Deputy Prime Minister Bill English said. Civil Defence officials said anyone remaining in the city should make accommodation plans tonight, and warned them to conserve water and boil drinking water for three minutes.

All flights across the nation were initially grounded as emergency crews worked amid the shattered buildings, including the cathedral, to evacuate the city centre and rescue those trapped. Police advised evacuees to go to the nearest civil defence centre. Amber Armitage said people were wandering around central Christchurch trying to get out but all exits from the city were blocked. There was a strong smell of gas and clouds of dust. A priest standing outside the rubble of the damaged cathedral told New Zealand television: "It is huge. We just don't know if there are people under this rubble." Mr Key said: "It is a very populated time with people at work, children at school." Christchurch Hospital was damaged but is operating and triage centres have been set up at Latimer Square in the city, Spotlight Mall, in Sydenham and Sanitarium at Papanui.

Christchurch resident Sean Scanlon said it was by far the biggest quake since the original September 4 quake. Police said the airport had been closed. All flights were initially grounded across the country as the national air traffic control centre in Christchurch was checked. Flights outside Christchurch resumed once that was done. An emergency service worker told Sky News that numerous people were believed to be in the cathedral tower when the quake hit. "I spoke to a witness when I got here earlier on," the unidentified worker said. "They said when the shocks happened there was people up in the tower. That's full of rubble. They're probably passed away. I'd like to go in but we've got to wait for search-and-rescue to go inside." The worker said he had entered the church twice briefly but saw no signs of life.

"I went into the chamber ... with another gentleman with hard hats on," he said. "I yelled out three times 'Anybody there?' Silence there, there was no replies. I've done that twice, 10 minutes apart. I believe there's nobody in there, and if there is they're probably unconscious or passed away." Christchurch's annual Festival of Flowers is being held in the city from February 11 to March 6, and its popular floral carpet display at the cathedral ended on Sunday. Australian search team on its way Australia has sent a 40-strong search and rescue team to Christchurch to help. Foreign Minister Kevin Rudd said about 8000 Australians were in the region around Christchurch and more than 2000 calls had been received by 3.45pm from worried loved ones. He said Australians in New Zealand could phone DFAT on +61 2 6261 3305 or the High Commission in the country on +64 4 473 6411.

Jimmy Sciascia, who was in a friend's house about 200 metres from the centre of Christchurch when the quake hit, said: ''The focus now is to get out of the city or to get out of the places where the quake happened. ''The roads are jammed. Traffic is moving quite slowly. Everyone appears to be heading out of the city.'' Mr Sciascia said the main city centre where the large buildings were located had been cordoned off by police and only emergency workers were allowed in. Shallow depth University of Canterbury Earth Sciences Professor John Townend told Radio New Zealand that today's event was connected to the quake on September 4. He said aftershock sequences did end but any of them could be quite big.

Christchurch is built on silt, sand and gravel, with a water table under it. In an earthquake, the water rises, mixing with sand. GNS Science said the quake struck 20 kilometres from the city at a depth of five kilometres. The New Zealand Herald reported that the jolt was felt in the capital Wellington to the north and the city of Dunedin to the south. Residents say it lasted about a minute. GNS duty seismologist Bill Fry said the acceleration of today's earthquake was larger in Christchurch city than the magnitude 7 earthquake last year.

"Instantaneously, they would have felt the greatest amount of shaking today. But the duration would not have been as long." The earthquake happened at a shallow depth of five to six kilometres below ground. In the city, the acceleration measured the same as the force of gravity. In September, the largest acceleration felt around the city was on its eastern side, and this measured 0.8 times the force of gravity. Today's earthquake did not last as long as the September quake, but Dr Fry said its duration had not been confirmed yet.

Destruction everywhere Kay Cowlishaw said there was destruction everywhere. "There's just water pouring out and sewage, the whole garage is filled with water. There are cracks in the road." A visitor to the city, Philip Gregan told AAP over the phone: "It was incredibly violent, very very scary. "We're all standing out on the street with sirens going off around us.

"Oh no, there's another one," he said while on the phone. "I want to get out of here." Tarmac on the road was cracked and water mains had burst, flooding the streets. Nathan, a Melbourne surgeon attending a medical convention in Christchurch, said he had seen major destruction around the city following the quake, which was followed five to 10 minutes later by a strong aftershock. He feared there would be fatalities, including at the cathedral in the main square where the steeple had been destroyed. "I'm over here at a convention in Christchurch and just in the middle of a session, you know, the speaker was speaking and suddenly the ground shook, and glass was breaking and it was really quite frightening," Nathan told radio 3AW.

"Fortunately nobody from our convention appears to be severely hurt but there's a lot of major destruction here in Christchurch. "I don't know if you know the church in the centre of town, the steeple has fallen over. I'm certainly fearful that there will be some fatalities among that, and a lot of the buildings just adjacent to the city square, the awnings of buildings have all fallen down and a lot of buildings around here, it looks pretty shaken up. All the water mains have burst. There's water seeping up through the roads. It's a fairly scary place to be right now. "The road has been buckled up, just like looking at bits of liquorice sort of burst up on the seam. It really is quite incredible." Buildings fall on to cars He said buildings had fallen on to cars, while "lots of second storeys have fallen onto first storeys".

"I guess a lot of us now don't know what to do. Some of us were thinking to go down the hospital to help out but we were told not to leave the area because it's not safe," Nathan said. Jared Cummings, from Melbourne, was on the phone to his father, John, in Christchurch just as the earthquake hit. "He said 'shit' and all I heard was nothing and then I heard my mother crying in the background," Mr Cummings said. He tried to call emergency services in New Zealand but couldn't get through, before talking to his parents again. "They were OK but their house was destroyed, massive cracks in the retaining wall."

He said his sister in Christchurch said there was huge damage to roads and bridges. Dunedin resident Katie Brock said she could feel the earthquake and the aftershock. "In Dunedin, the quake felt like a side-to-side roll, which seemed to last a long time," she said via email. "Time enough for me and my workmate to look at each other, say: 'Shit! It's an earthquake!'; think about what do do, and then stand under the door frame until it stopped. "A little while later there was another aftershock. Not so strong, but freaky after the first one."

Sky News footage also showed people being taken from buildings and others running down the streets that were filled with rubble and parts of fallen buildings. One man named Michael in central Christchurch, holding a bloody tissue to his nose, told Sky News he was hit by rubble. "I've just gotten a bash on the face," he said. Australian thoughts with quake victims: Swan Deputy Prime Minister Wayne Swan said the thoughts of Australians were with the victims.

"We hope that there is good news," he told Parliament today. Foreign Affairs Minister Kevin Rudd said there were deep concerns about the loss of life and serious injuries. "For the people of Christchurch this just isn't fair," he told the National Press Club in Canberra, ahead of his address on foreign policy. "The damage is large, it's the middle of the working day, and the earthquake has not been deep from the surface." Mr Rudd referred to Australia's solidarity for its Kiwi friends at "a horrible time" for the people of Christchurch.

Opposition Leader Tony Abbott said his thoughts and prayers were with the people of Christchurch. "Millions of Australians have family and other links across the Tasman," he told reporters in Canberra. "This is a very sad time and our hearts are with the people of New Zealand." Mr Abbott said it was important the Australian government responded appropriately to the disaster. "I'm sure that we will be only too happy to meet any requests for assistance the New Zealand government might make."

Last September's quake The epicentre of last September's quake was 40 kilometres west of Christchurch at a depth of 10 kilometres. About 100 people were treated at hospital with earthquake-related injuries but no one was killed. The quake caused causing billions of dollars of damage. The first jolt, at 4.35 am on Saturday, September 4, lasted about 30 seconds.

Four days after that earthquake, GNS Science warned that aftershocks might continue for some time. The city has been shaking regularly since, with aftershocks up to 5.1 magnitude recorded. Christchurch is the largest city in New Zealand's South Island and the country's third largest. New Zealand sits on the so-called "Ring of Fire", the boundary of the Australian and Pacific tectonic plates, and experiences up to 15,000 tremors a year. It averages at least one a day that is magnitude 4.0 or stronger. Loading

A Qantas spokesman said a Sydney-Wellington flight was diverted to Auckland. Another Melbourne to Auckland flight was being held back in Australia while other flights departing Auckland were put on hold, he said. stuff.co.nz, smh.com.au, AAP, AFP and Reuters

