Christchurch

When I was at university in Christchurch in the late 1970's I did a degree in Geography. Part of that degree covered reasons why cities grow where they do. 'Human Spacial Distribution' I believe it was called. Our attention was drawn to things like high fertility, transport nodes like suitable ports and navigable rivers, coach 'night stop' distances from other places, location of minerals or tourism possibilities like spa water, skiing ... the list was to be learned and regurgitated for exams.

At one point I distinctly remember our lecturer asking us to suggest the reasons for the location of the city we presently lived in, Christchurch. We cited the fertility of the plains, proximity to the sheltered port (Lyttleton) for the whaling ships and the rain-shadow effect of the Southern Alps providing a climate suitable for growing sheep and wheat on land conveniently previously cleared of bush (for easier hunting of Moa).
He agreed with all this, but said that there was something very important that made this area not suitable for a city.
Then he began to talk about what a dangerous place Christchurch was. He said it had been built on swampland, and the youngish, fine, even-sized silty sand that made up large areas of this particular swamp meant that, if jolted, as in an earthquake, they would no longer be able to 'hold onto their water' and the areas would 'liquify'. Anything built on top of this material would collapse. In this way we learnt about liquefaction.