Rescue crews with sniffer dogs fanned out across the city in search of survivors, some of whom sent desperate text messages and made cell phone calls from under the wreckage of the 6.3-magnitude quake.

Toby is a survivor who was trapped for several hours in a collapsed building before he was pulled to safety. "I was banging on the metal yelling out 'help' because my voice was better than theirs. Luckily one of them got out before me," he said.

His mother Tania was nearby and relieved to be reunited with her son. "From where he was on the fourth floor, really I thought he was gone. But I chose not to leave here, until I knew for myself that he is alright," she said.

Television footage showed several multi-story buildings that fell in on themselves or into the streets, as well as the collapse of the Christchurch Cathedral, whose stone spire crumbled into a city square. Rescue workers say they believe people were in the tower at the time.

Helicopters were seen fighting fires and plucking stranded workers from the roofs of high-rise office towers.

Domestic flights were disrupted at New Zealand's Auckland airport stranding hundreds of travelers, many who were taking the delays in stride.

"I just said to that lady, that I got my book, it could be awhile, but I see we're lucky compared with, you know, not complaining,"said one woman.

The earthquake, which struck at midday Tuesday, was the second to hit Christchurch in the past five months. The city came through a 7.1-magnitude quake in September without loss of life. But seismologists said Tuesday's quake struck closer to the city and much closer to the surface, making it far more intense.