Nine U.S. Congressmen attending the meeting were reported to have left the city before the quake struck.
Tour guides at the Tasman Glacier in the Southern Alps say the quake shook some 30 million tons of ice to off the glacier, forming icebergs in the lake. The falling ice created waves up to 11 feet high, which swept up and down the lake for 30 minutes.
The Christchurch airport, initially closed, was reopened Tuesday to emergency flights, and airport officials said domestic flights would resume on Wednesday.
New Zealand’s worst earthquake was one that struck in 1931 at Hawke’s Bay on the country’s North Island, which killed at least 256 people.
Jeff Peters, who runs a luxury motel in Christchurch less that a half mile from the cathedral, said the earthquake sent microwave ovens, plates and cups in his guest rooms flying.
“Sure we’ve come back from the last one, but what do we do now?” he said. “Because so much of the city has been destroyed.”
Associated Press writers Steve McMorran and Ray Lilley in Wellington, New Zealand, Sean Yoong in Kuala Lumpur, Malaysia, and Jay Alabaster and Tomoko Hosaka in Tokyo contributed to this report.