A large quake has struck Christchurch, with reports of buildings and houses down.

Witnesses said there were buildings down all around Cathedral Square in the city, with the church destroyed.

Christchurch resident Sean Scanlon said it was by far the biggest shake since the original September 4 quake. The power was out and phone lines jammed.

The city was being  shaken by a series of heavy aftershocks.

Christchurch Hospital was being evacuated, a spokewoman for the hospital said.

Kay Cowlishaw said there was descruction everywhere.

http://www.smh.com.au/world/huge-quake-hits-christchurch-20110222-1b356.html

Multiple fatalities have been reported after a powerful 6.3-magnitude earthquake struck Christchurch on New Zealand's South Island, police say.

The tremor, which hit at 1251 (2351 GMT on Monday) only 10km (6.2 miles) south-east of the city at a depth of 5km (3.1 miles), caused widespread destruction.

The fire service said numerous people were trapped in buildings, and a state of emergency has been declared.

The damage is said to be far worse than after September's 7.1-magnitude quake.

Two people were seriously injured by the tremor, whose epicentre was further away and deeper. It caused an estimated $3bn in damage.

There have been several aftershocks since last September's quake, with a 4.9 magnitude tremor hitting just after Christmas.

http://www.bbc.co.uk/news/world-asia-pacific-12533291

Mr Key said New Zealand may be witnessing "its darkest day".

• At least 65 confirmed dead
• Second major quake to hit city in five months
• Extensive damage in city, power cuts
• City has run out of ambulances
• 5.6-magnitude aftershocks recorded

• http://www.abc.net.au/news/stories/2011/02/22/3145879.htm

The upheaval wrought by the 22 February earthquake in Christchurch, NZ, is illustrated in new radar imagery.

The Magnitude 6.3 tremor killed more than 160 people and shattered a city already reeling from a previous seismic event in September.

Data from the Japanese Alos spacecraft has been used to map the way the ground deformed during the most recent quake.

It shows clearly that the focus of the tremor was right under the city's south-eastern suburbs.

The type of image displayed on this page is known as a synthetic aperture radar interferogram.

...

The coloured bands, or fringes, represent movement towards or away from the spacecraft.

In this interferogram, the peak ground motion is almost 50cm of motion towards the satellite.

http://www.bbc.co.uk/news/science-environment-12668190