There will be blood, according to U.S. Geological Survey scientists: As the world population grows we can expect more individual earthquakes that kill lots of people and as a result see more individuals die from quakes than ever before.
Engineering geologists Thomas L. Holzer and geophysicist James Savage, writing in the new issue of the journal Earthquake Spectra, predict the 21st century will see 21 quakes with a death toll of 50,000 or greater (plus or minus four), with nine of those killing more than 100,000. In the century just passed, there were seven quakes that killed at least 50,000 people, and four that killed 100,000 or more.
If United Nations’ population estimates bear out and we hit 10 billion by 2100, some 2.6 million people could die from quakes in this century—doubling the 20th century’s grim tally. And we’re well on the way to exceeding that prediction: The 2004 Boxing Day quake/tsunami in the Indian Ocean killed at least 230,000 while the 2010 Haiti quake killed 316,000.
Understand, the scientists aren’t predicting more quakes overall compared to what we've felt over the preceding half-millennia—just that the human damage from quakes will be greater.
In one sense, Holzer and Savage’s predictions seem utterly intuitive: More people mean more deaths. But in another, the correlation is not so obvious. That’s because in an increasingly urban world, quakes don’t kill people, buildings kill people.
Over the weekend, for instance, Kelin Wang of the Geological Survey of Canada discussed earthquake prediction during a session at the American Association for the Advancement of Science meeting in Boston. But his takeaway message wasn’t that we should expect a golden age of advance warning, built upon the successful call on the Haicheng earthquake of 1975, but rather that any “passion for prediction” has been replaced by an emphasis on mitigation.
So much attention has been focused on forecasting quakes, he said, “because of a lack of confidence in our buildings.” (Stories about migrating toads and hyperactive snakes also spur interest, of course.) But better and safer structures can and do prevent the shocking death tolls. Looking at Italy’s deadly L’Aquila quake, for example, where the lack of a prediction led to manslaughter convictions for Italian seismologists, Wang noted that the city’s up-to-date building codes did not extend to require the retrofitting of its trove of beautiful historic structures. In fact, wary locals tended to sleep outdoors when they felt shaking, a behavior conditioned by the area’s history of powerful temblors.
If applied (see: Fukushima, Japan, 2011), and not papered over (see: Sichuan, China 2008), modern seismic-safety techniques make a difference, Wang, the USGS scientists, and the readers of Earthquake Spectra (which serves the all-about-better-buildings Earthquake Engineering Research Institute) all note.
"Without a significant increase in seismic retrofitting and seismic-resistant construction in earthquake hazard zones at a global scale,” Holzer was quoted in a USGS release, “the number of catastrophic earthquakes and earthquake fatalities will continue to increase and our predictions are likely to be fulfilled."
And in that sense, Wang heartily endorsed the idea of long-term quake prediction, relying more on maps than news bulletins. In short, his recommendations for saving lives involves knowing where the Big One, or Big Ones, are likely to hit—and building accordingly.