A lucid look at decades of failed attempts to reach seismology’s Holy Grail: the precise prediction of when earthquakes will occur.
Science is messy. For every step forward on the road to truth, there are two steps in some other direction. And the way toward earthquake prediction, the Holy Grail of seismology, is littered with the dashed hopes of those who have failed.
“Even well-trained scientists, even brilliant scientists, can fool themselves in their quest to prove something they believe or want to be true,” says Susan Hough in her engaging new book, Predicting the Unpredictable: The Tumultuous Science of Earthquake Prediction. “… It is a hard thing for any scientist to do, to admit they have been on a path that isn’t going to go anywhere.”
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Sifting through the rubble of more than a century of fruitless effort, Hough tells how California, a state living dangerously on the boundary of clashing tectonic plates, became a hotbed not only of earthquake science but also earthquake-prediction fiascos.
Scientists learned to map quakes and measure their motion, laying the foundations for strict building codes that saved countless lives. They could accurately predict that the San Andreas Fault was overdue for a massive quake … someday. But virtually every time they ventured to warn the public that a quake was coming on or before a specific date, they were wrong.
There was, for example, the famous “Palmdale bulge,” a so-called warping of the San Andreas Fault in the Mojave Desert, reported by the U.S. Geological Survey in 1976 as a sign of an impending quake. It turned out to be an error in measurement.
There were the two men who studied underground “rock bursts” and predicted that a major quake would strike near Lima, Peru, in 1981. “Did they get the idea from The Tibetan Book of the Dead?” a colleague asked. No such quake occurred.
And there was the USGS again in the late 1980s, armed with the information that magnitude 6 earthquakes struck Parkfield, Calif., every 22 years on average and boldly predicting a moderate quake on the San Andreas Fault near the town by 1992. The quake, when it finally came in 2004, was 37 years after the previous one. It became a famous example of the “irregular regularity” of earthquakes. “Fools and charlatans” was the epithet that Charles Richter, creator of the Richter magnitude scale, reserved for those who claimed to make precise earthquake predictions.
But Hough, a seismologist with the Southern California Earthquake Center, a fellow of the American Geophysical Union and the author of several other books on earthquakes, treats the many failures and dead ends of her profession with sympathy. She is focused on the business of science, and science almost always proceeds in fits and starts. Skeptics may engage in hazing, careers may end in regret, but debunking bad ideas is part of the testing that must go on.
“One can’t hope to push boldly into the frontier of knowledge and pick the right path every time,” Hough writes. “… Science goes wrong when scientists refuse to recognize evidence that is staring them in the face, telling them they are on the wrong path.”
The fault line running through Hough’s tale is a tantalizing notion: Reliable earthquake prediction that would save countless thousands of lives was right around the corner. She shows how scientists measured real precursors to earthquakes, such as changes in the chemistry and level of groundwater; electromagnetic signals called earthquake “lights;” unusual releases of gas or heat along a fault line; changes in the speed of seismic waves; and — the most popular phenomena of all — changes in the patterns of small and moderate quakes. These apparent signals were documented both before and after the fact. But to date, no one has been able to use them to make a successful prediction. The problem, Hough posits, “might not be solvable.”
Looking beyond California, Hough examines quakes in Hawaii, Sumatra, Chile, Japan, Iran and even Missouri, where a big one struck in 1812, toppling chimneys in Louisville, Ky., and ringing church bells as far away as in Charleston, S.C. A year later, an aftershock rocked the heartland, causing the Mississippi River to flow briefly backward and carry boatmen upstream.
In one of her most compelling stories, Hough draws aside the curtain on the magnitude 7.3 quake that struck Haicheng in northern China in 1975, killing 2,000. There had been rumblings of the earth leading up to it, and the Chinese authorities claimed to have evacuated the population in time, saving untold thousands of lives. They relied in part on citizen reports of well-water fluctuations and strange animal behavior in the weeks before the quake, especially 100 snakes seen emerging incongruously from winter hibernation.
The news from Haicheng helped boost the funding for earthquake safety in the U.S., but it was also a shot in the arm for prediction scientists, who spent years following leads that were later discredited. As Hough tells it, the Haicheng hype was partially manufactured. In any case, the euphoria was short-lived. A year later, in 1976, the Chinese government reported 250,000 deaths in Tangshan, where a massive quake struck without warning.
Predicting the Unpredictable is a lucid, nuanced book, sprinkled with arresting photos, diagrams and sidebars for the lay reader. Occasionally, Hough provides too much information on the ins and outs of one esoteric debate or another, perhaps out of deference to her peers. She is at her best when she deftly compares earthquakes to popcorn popping, or invokes comedian Jay Leno to drive home a point. (“Hey don’t do me any [favors] — I can predict aftershocks, OK? You know when they happen? Right after an earthquake.”)
Most scientific research goes on behind closed doors. Hough’s book reveals the inner workings of the profession even as it stumbles, like Alice, into Wonderland. After a century of failed predictions, most seismologists in the U.S. and Europe have become, at best, agnostics on the subject. They’re focused instead on how faults interact with neighboring faults, how earthquakes interact with other earthquakes, and how the earth’s brittle crust interacts with more plastic layers below.
One thing scientists know for sure is that the southern San Andreas Fault has been 10 months pregnant for decades. The Big One could hit California anytime — maybe by the time this magazine goes to print, or maybe in 50 years.
“And so here we sit, with reason for concern, but grossly imperfect knowledge,” Hough concludes. “What do we say? What can we say? There’s a bogeyman out there; we know it’s scary and dangerous, but how scary and dangerous, we really don’t know. And exactly when it will make an appearance, we don’t know that either.”