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.