Only two serious injuries were reported from the quake as chimneys and walls of older buildings were reduced to rubble and crumbled to the ground. Prime minister John Key said it was a miracle no-one was killed.
Part of the reason the city escaped major injuries was because the quake happened before dawn, Mr Key said.
"If this had happened five hours earlier or five hours later (when many more people were in the city] there would have been absolute carnage in terms of human life," he said last night.
The quake cut power across the region, blocked roads with debris, and disrupted gas and water supplies, but Christchurch Mayor Bob Parker said services were being restored.
As the recovery work gathered pace, forecasters warned strong winds would buffet the area, creating problems with flying debris.
WeatherWatch forecaster Philip Duncan said gale force winds of 40mph and stronger "could cause serious issues for trees and buildings that were weakened in the earthquake".
Specialist engineering teams began assessing damage to all central city buildings yesterday, said Paul Burns of the city's search and rescue service.
Canterbury University geology professor Mark Quigley said what "looks to us that it could be a new fault" had ripped across the ground and pushed some surface areas up. The quake was caused by the ongoing collision between the Pacific and Australian tectonic plates, said Prof Quigley, who is leading a team trying to pin down the source of the quake.
"One side of the earth has lurched to the right - up to 11 feet - and in some places been thrust up," he said. "The long linear fracture on the earth's surface does things like break apart houses, break apart roads.