Hey TB - sorry for the brevity of my response earlier.....I was flat out last week. So here are a few things to make you feel a bit better.....firstly that there is no significant uptrend in normalised disaster damage from 1980 - until now. Some people will argue that this is not the case and that climate change is effecting meteorological events - this is not the case (i could rabbit on for hours about this point but will not). Essentially the reason that the numbers are going up is because of societal factors - population, wealth and inflation. Effectively we continue to build stupid houses in stupid loctions and we now have more to lose. Earthquakes though are what we call a geological event - no climate change impacts on those!!! The long term occurrence of EQ's are caused by the relative motion of the earth's plates - damage causing earthquakes on a given fault are typically long - in excess of 100 yrs on the most active faults (Japan) and as long as 10,000 years on more technically stable regions (Australia).
With Christchurch we have seen a lot of spatial and temporal clustering (similar to Sumatra in 2004) but no clear pattern. So if you look at these events over a short time frame (relatively speaking) like 20 years we will not see trends similar to those of weather related events.
In NZ, along with Japan and the US seismic provisions were introduced into the building codes in the early part of last century - the goal here was protecting life - recall that EQ's do not kill people generally speaking - its the buildings that fall down that do the damage. Since about 1970 the code took a turn and the design changed to incorporate structures that had the ability to withstand collapse. This has resulted in a dramatic decrease in the incidence of both building collapse and loss of life. People still see the present level of destruction as unacceptable and so further changes have been made in the last 30 odd years and now buildings are designed to achieve a set performance objective given a specified annual probability of occurrence - death, dollar losses and downtime (business losses) - also known as the 3 D's.
Essentially the cause of the escalating damages globally is defective siting, design and construction. Earthquake prediction is not the key to risk reduction - its improvements in EQ engineering and there has been significant advances made in the last 10 years. NZ is at the forefront of this. So whilst yes it may not be the best news you have ever heard you should sleep a bit better knowing that you reside in one of the safest active EQ spots on the planet!!!
From an affordability point NZ has been able to withstand the quakes fairly comfortably - especially when compared to poorer third world economies. The great thing is that at least there is a mechanism (although the EQC may not be perfect) to help communities rebuild after such dramatic events.
Hope that makes you feel a little better
