Seismic risk mitigation is the greatest urban policy challenge the world confronts today. If you consider that too strong a claim, try to imagine another way in which bad urban policy could kill a million people in 30 seconds. Yet the politics of earthquakes are rarely discussed and, when discussed, widely misunderstood.
Take Japan's Sendai earthquake on March 11, which released 600 million times the energy of the Hiroshima bomb. The ensuing partial meltdown at the Fukushima Daiichi nuclear power plant prompted international hysteria about nuclear power, but few seemed to realize that a far deadlier threat had been averted. As seismologist Roger Bilham aptly put it, houses in seismically active zones are the world's unrecognized weapons of mass destruction — and Japan's WMD didn't go off. Its buildings — at least those that weren't swept away by the accompanying tsunami, a force of nature against which we are still largely helpless — remained standing, and the people inside survived.
That so few buildings collapsed in the earthquake was a human triumph of the first order. But cities around the world seem happy to ignore the earthquake threat — one that is only growing as the cities themselves get bigger and bigger.
The Japan quake was not the catastrophe it could have been because the country learned from experience. In the wake of the 1995 Kobe quake, in which 200,000 buildings collapsed, Japanese engineers took extensive measures to reinforce buildings and infrastructure. They installed rubber blocks under bridges. They spaced buildings farther apart to prevent domino-style tumbling. They introduced extra bracing, base isolation pads, hydraulic shock absorbers. A minute before the March earthquake, seismic monitoring systems sent warnings to Japanese cellphones. Elevators glided obediently to the nearest floor and opened. Surgeries were halted. Videos from Tokyo show skyscrapers swaying gracefully, like cornstalks in the wind. Not one collapsed.
Cities at risk
But many of the world's biggest cities are at massive seismic risk, built more like Port-au-Prince, Haiti, which was devastated by an earthquake in 2010, than like Kobe. Eight of the world's 10 biggest cities are built on fault lines, and they are growing larger every day. The urbanization trend is continuing upward, as is the trend of housing migrant populations in death traps. As a result, it's likely that before long we'll see a headline announcing, "1 Millon Dead in Massive Earthquake."
Yet, just as we know how to build airplanes that don't crash, we know how to construct buildings that don't collapse. We also know which cities are most at risk: Bogota, Cairo, Caracas, Dhaka, Islamabad, Istanbul, Jakarta, Karachi, Katmandu, Lima, Manila, Mexico City, New Delhi, Quito and Tehran. Los Angeles and Tokyo are prime candidates for a major quake, but they will probably survive because they are well-built — though Los Angeles could do better.
It's tempting to think that people in certain countries are cavalier about the risk because they're poor. The argument goes like this: Safe houses cost more to build than cheap ones. Cement watered down with sand stretches further. People in poor cities don't have the money to build safe houses, or if they do, they have decided to use it to mitigate more immediate risks such as hunger.
If wealth was all there was to it, the solution would be, if not simple, at least obvious: To prepare for an earthquake, promote economic development and cross your fingers. When a country becomes wealthy enough, the problem will solve itself.
This theory has been voiced in Istanbul, where I live. Mustafa
Erdik, chairman of the Department of Earthquake Engineering at Bogazici University, has suggested that Turkey's best hope is rapid economic growth. If growth happens fast enough, he says, property owners will be able to replace the worst housing stock before the ground starts shaking. If we look at it this way, we see seismic risk reduction as a paradox: The best way to reduce the risk is to ignore it.
The idea is tempting and elegant. But it's wrong.
Money isn't everything
Wealth in and of itself is not enough to get people to take earthquakes seriously. Here is the evidence. On Feb. 27, 2010, a magnitude 8.8 earthquake struck near the city of Concepcion, Chile. Though the epicenter was not at the heart of the city, this quake was 100 times bigger than the one that leveled Port-au-Prince. It was so massive that it shortened the length of the day by 1.26 microseconds and moved the Earth on its axis by eight centimeters. When it was over, the entire city of Concepcion had been moved three yards to the west.