I have during this day heard much more and learned a lot about this tragic event.
Seems New Zealand builds far better than we do.
And also the Wellington suffers earth quakes every bit as bad.
So building else ware seems out.
It is true that Christchurch is built on a cross over,subject to more quakes.
I do not know enough to judge but any new city may be build in safer ares one day, but suffer the same fate.
Lets hope for a miracle,that more live people than expected are found and that plus giving a few dollars is about all we can hope for.

Belly:

Christchurch was built on poor sandy soil and as indicated in the media due to earthquake activity it liquified, that is, the shock squeezed the water to the surface undermining the building foundations. To build in an earthquake zone buildings that will withstand earthquakes up to 7 on the richter-scale would require the foundations to be sunk to solid bedrock which apparently Christchurch doesn't have. The other option is to build low buildings on "raft" structures which literally float on the earth's surface. Both methods are very expensive and the only logically solution is to abandon the central business district and build a new center where bedrock foundations would be close to the surface. That of course requires the type of structural designs practiced in earthquake zones around the world such as Southern California and Japan.

I think the freaky thing is that Christchurch locals before September were just not used to earthquakes. The South Island very rarely shook. Wellington and most of the North Island is and the peeps are well used to them from Wgtn on up. Nothing like watching the ground roll and listening to the amazing sound of a quake coming.

September gave the Ch-Ch locals a big fright but nothing like this latest shallow shake. It was mostly built on a swamp btw and did have some very old and lovely stone heritage buildings. A number of which I spotted now shattered.

Some areas were completely untouched by the quake and did not lose phone, tv, power etc while some got flooded with the stinky water. And we’ve all seen what happened inside the four avenues (town centre).

Newer buildings… and you used to be able to hear and feel them being built would ram foundations down until the solid stuff was found.

Build again, hell yeah. But the word from the early twenties aged crowd is they want out… weird because I thought young people would kind of more… well, just more. Speaking to older locals they seem very upset and we know the body count keeps rising but I haven’t heard mention of wishing to leave their city.

They should use shipping containers as building units. Very rapid construction times, many architectural styles could be reproduced, and the structures would fair far better under the stress and strain of an earthquake. The building cost is also about 2/3 of conventional methods, and that cost would likely fall as builders gained familiarity with the technique.

My suggestion is simple. Build again. Build better. Build with the assumption that what you build will, one day, be knocked down again.

The reality is that if we abandon all areas with a chance of natural disasters, we seriously reduce our options. The North Island of NZ would be a no-go zone. I lived there for three years without a noticeable earthquake (but many memorable earthquake drills at school), then moved to the relatively earthquake-free extreme north of Sydney. I can still remember the far-distant rumble of the Newcastle earthquake, and a couple of dislodged tiles on our roof. Brisbane would be a no-go zone. I lived there for 12 years with only flash flooding. North Queensland would be a no-go zone. I have lived here for six-and-a-bit years and have only recently felt the force of a significant cyclone. The list could go on.

People should be made aware of the threats, and certainly nobody should be forced to rebuild in Christchurch. Mitigation strategies should be put in place, but nobody should be told that they are foolproof. Nobody should say that an event is a "one-off": I assume that something as big and nasty as Yasi will come my way again, and people in Christchurch should assume that something as big and nasty as their earthquake will come again. The Victorian bushfires, the SEQ floods ... disasters happen. Even if we rebuild somewhere safe, or to a higher standard, we must always assume that we are at the mercy of these disasters. The loss of life is a tragedy, and steps must be taken to learn from current losses to minimise future losses, but we must never convince ourselves that we can prevent them altogether.

Lexi I did not know it was built on sand or swamp.
Knew about the liquidation, and have been on ABC NEWS 24 for days.
Experts are saying Christchurch latest buildings are world class in earth quake construction,but admit to a few failures.
Older buildings have been described as poor, concrete blocks said to be held together by what amounts to sand.
After Septembers quake worlds best quality measuring equipment was put in place.
We will in time hear much more about this ones strength.
Christchurch we are told sits on a fault that crosses over under it.
from one side of that Island to the other coast of the other.
Maybe the plates no longer move as in the past?