Earthquakes now endanger more people than ever. The world population has more than doubled in the past 50 years and, by 2007, half of the planet’s 6.6 billion people will be living in urban centers. Because more than 380 major cities lie on or near unstable seams in the Earth’s crust, one seismologist has come to a grim conclusion: A catastrophic temblor sufficient to kill 1 million people could occur, on average, once per century.
The prediction is based on tallies of recorded earthquake occurrences over hundreds of years. If quakes of similar size and distribution were to recur in today’s demographic landscape–which features megacities such as Mexico City, home to 18 million people–the consequences would be disastrous.