Could the Kashmir earthquake have been predicted? And why are American scientists rebuilding the 1918 virus—one of the most virulent ever?by Philip Ball / November 20, 2005 / Leave a comment
Predicting earthquakes Could the Muzaffarabad earthquake in Kashmir, for which the death toll stands at nearly 40,000, have been foreseen? And if it could have been, would it have made much difference?
Earthquake fatalities depend not only on the quake’s magnitude—a measure of how much energy it releases—but on geological and demographic factors. In densely populated Kobe in 1995, a magnitude-6.9 quake claimed over 6,000 lives, despite Japan’s relatively advanced building technologies, because the region’s soft rocks liquefied. In contrast, the 1989 Loma Prieta earthquake in California was magnitude 7.1 and the epicentre was just ten miles northeast of Santa Cruz, yet only 68 people died.
Earthquakes in less developed countries are usually no bigger than those in rich countries, but are often far more lethal because buildings are not made to withstand them. Without the resources for quake-proofing, the only option is prediction and evacuation. Some argue that this is possible. In 1975, Chinese seismologists claimed that they successfully predicted a 7.3 quake in Haicheng, northeast China. Although more than 1m people lived near the epicentre, they were evacuated and there were “very few” fatalities (about 1,300, which may indeed count as very few in China in 1975). Whether this was a genuine prediction or party propaganda is still disputed. The foresight seemed to fail for the 1976 Tangshan quake, which killed at least 240,000.
Charles Richter, who devised the earthquake magnitude scale, was among the sceptics. In 1977 he grumbled that “journalists and the general public rush to any suggestion of earthquake prediction like hogs toward a full trough.” Earthquake prediction, he said, “provides a happy hunting ground for amateurs, cranks and outright publicity-seeking fakers.”
Many scientists still feel that way. Despite claims that major earthquakes on a given fault recur periodically, the latest thinking tends to prefer the idea that these ruptures are similar to stock-market fluctuations (another favourite hunting ground for phantom patterns) and avalanches: they are inherently unpredictable, so that you can never tell when they will come or how big they’ll be. The technical term for this is “self-organised criticality.”
But that’s not to say the earth is merely capricious, or that prediction is hopeless. It is possible to monitor the build-up of strain on a fault and so to estimate how close it is to slipping. But that requires a lot of information to be gathered over space and time, and only…