This is just a quick update to my earlier post on l'Aquila, as the recent Christchurch earthquake demonstrates a point that I didn't emphasise strongly enough there. The whole "prediction" aspect is a bit of a red herring, everybody knew that an earthquake was going to hit l'Aquila sooner or later. Regardless of what scientists said about the short-term chances of an earthquake, the town should already have been prepared. Comparing l'Aquila with Christchurch shows what a difference this preparation can achieve.
First a bit of background on the two quakes. The l'Aquila quake was Mw 6.3, at roughly 9 km depth; Christchurch was a Mw 7.1 at a depth of 10 km. L'Aquila had a population of 73,000, Christchurch 370,000. From these details, you would expect far more casualties in Christchurch.
However, this is not the case. Remarkably, in Christchurch only 2 people suffered serious injuries. The l'Aquila quake lead to 308 deaths. How did Christchurch escape so unscathed?
Earthquake damage in Christchurch. Photo CC-BY Flickr user Benjamin Humphrey
There is an element of luck to the low death toll. The quake happened 4:35 am local time, when most people were sleeping. A lot of the pictures of damage show areas of the city centre, with fallen masonry on the street. Had the streets been busy at the time it could have been much worse. This doesn't, however, explain the discrepancy between l'Aquila and Christchurch, as the l'Aquila quake also took place in the early morning (at 3:32 am local time).
More importantly, the damage done to buildings in Christchurch was far less than l'Aquila. The picture above is an isolated example even here you can see in the background undamaged buildings. The reason for this? Properly enforced building codes. Dull though it sounds, building regulations are probably the biggest life saver in an earthquake. While Italy does have stringent building codes, at least for earthquake-prone areas, many of the buildings in l'Aquila were not built to them. Organised crime is a big problem in the Italian construction industry, especially in the South. It appears that rouge builders in l'Aquila cut corners to save money, and the inhabitants paid the price.
There are other thing that New Zealand does well to cut the impact of earthquakes. Awareness campaigns make sure that everyone knows what to do in a quake, and mandated government earthquake insurance provides an instant rebuilding fund. GoodSchist has a nice podcast which expands on this. All of these obviously contribute, but in my opinion it is the building regulations that are crucial. It may be cliché, but it is true: Earthquakes don't kill people, falling buildings do.
Much has been made of the difference in impact of the Christchurch quake with the Haiti quake, and the effect poverty has on expanding the death toll. However, New Zealand and Italy both have roughly the same GDP per capita, of about $29,000. The failings of l'Aquila are not due to poverty. Neither are they due to scientific ignorance. They are political. Too little emphasis was placed on ensuring buildings would withstand an earthquake. This is a lesson every country faced with natural disasters can learn.
UPDATE: I discuss some of the points raised in comments on a new post here.