Web edition: August 27, 2010
Print edition: September 11, 2010; Vol.178 #6 (p. 32)
Thanks to the planet’s exploding population, more than a billion housing units will be built during the next half century. Many of those will be in urban areas that are vulnerable to catastrophic earthquakes such as the magnitude-7 quake that killed more than 200,000 people in Haiti in January. Roger Bilham, a seismologist at the University of Colorado at Boulder who studies the earthquake vulnerability of cities, sat down recently with Science News contributing editor Alexandra Witze to talk about why builders routinely flout earthquake-engineering regulations, and how urban residents can be kept safe.
What factors tend to affect whether a government enforces good earthquake-resistant building codes?
It’s always difficult to generalize. I just got back from Pakistan, where we have a big project measuring the deformation of the western edge of India. Islamabad is a relatively new city, with earthquake codes; there’s really very little that should be wrong with it, particularly because the military have huge control. Not that they are trying to build quake resistance, but they prevent people building anywhere they want. If you go further south, to Karachi, the reverse is true. Corruption is a way of life there. If you want to put up a building without building codes to save money, there are many ways to do it.
How can society reduce the death toll in big earthquakes?
There’s a top-down problem — a gap between the important buildings of a city, like the town hall and hospitals and schools; well, it should be schools. Building codes are usually applied for civic structures. But where are most people being killed? In their own dwellings. Governments aren’t really interested in that level of construction, but that’s where the effort needs to go. U.N. inspections need to get it across, right at the village level, that you don’t just start building. You need permission to do it, along with instructions about what to do.
You’ve proposed creating a special United Nations task force that would enforce local building codes for quakes. How would that work?
I envisage not a U.N. building inspector on every street corner. I envisage a task force where they go to cities and say, how are your inspections done? Let’s see what your building code is and what steps you take to have inspections. And we’ll explain how we think you should do it to avoid people circumventing the laws that you yourselves want to apply. It’s not like a police force where you prevent individual laborers or contractors from assembling buildings. You actually show the government how to implement their own laws seriously.
Everywhere I go there are in fact building codes. Haiti had a building code; it just wasn’t implemented ever, except by engineers. I saw buildings go up in Haiti that were perfect, the buildings still standing after the quake. But when a developer is involved he’s trying to maximize profits. Unfortunately, developers tend to be the bad guy.
What this U.N. task force has to do is be extremely serious about working on showing the world’s governments — particularly the ones in the developing nations — how to stop killing their own people. That’s unacceptable.
Seismologists knew that Haiti was at risk of a big quake before one struck in January. Why was there still so much devastation?
We got a lesson from the Haiti quake — you can have a tragic disaster from a quake that doesn’t break the surface and has little surface effect. There’s hope that one might be able to learn about past quakes by looking at submarine slides offshore, by extending geological studies to offshore regions. We could get at the tsunami hazards. The difficulty in improving the seismic risk picture in the Caribbean is the absence of much of a paleoseismic record, and the absence of submarine studies.
The problem with Haiti imposing a building code is that they can’t impose anything. The best intentions of engineers and scientists are pointless in the face of human nature.
Is the situation likely to change?
What we have to do is to educate at a very elementary level. When we go to school we’re shown how to bake a cake and do wiring and carpentry. Nobody ever shows us how to mix a bag of cement with some sand.