I am somewhat of a scientist and rationalist, and after seeing and hearing remarks of the rebuilding of the Christchurch CBD, I had to share a few remarks.
The liquefactions of those quakes are going to cause severe land subsidence, it just makes sense that those thousands of tonnes of silt, sand and so on are causing large water hollows beneath the surface, known as aquifers, so the land must sink causing future undulation.
It is comparable to volcanic eruptions when thousands of cubic kilometres of ash and magma are spewed into the atmosphere, thereby causing earthquakes and land shrinkage.
It will be a huge error if the CBD is rebuilt on the present unstable site, it must be rebuilt a few kilometres south which will be cheaper than messing about by rebuilding insitu, with the inevitable future shocks.

Ernest Izett, Tauranga.