About two weeks ago GNS announced some preliminary results (link) from their investigations into faulting in Canterbury responsible for the September and February earthquake events. A key finding was that there was roughly a 23% chance of another temblor in the Richter 6-7 range occuring in the next 12 months.
The media predictably blew up the 1 in 4 chance of it happening, while ignoring the 3 in 4 chance it wouldn't. There is some good extended discussion of what that means and the media reaction at Sciblogs here (including the interesting observation that the risk is no more than Wellington's, although we have always been told Wellington is high risk so I'm not sure how reassuring that is to Christchurch residents).
Unfortunately though, as events yesterday proved, 1 in 4 is still not zero. One blogger's account of yesterdays event is quite telling, not only for what it describes, but also what it implies, and for how routine some things are getting for the residents.
It is strange at the moment to hear people openly discussing on-line whether a major NZ city should be abandoned, or whether it is appropriate to suggest people leave. While hard to take seriously in a wider sense of totally abandoning the city, the fact such a thing is being discussed at all is slightly weird and surreal, and would have been unimaginable still less than a year ago. It will be interesting to see what Christchurch looks like twenty years from now.
Edit: This morning (wed 15th) GNS has revised their estimation to 30%.