From Wednesday’s paper: No one could have predicted L’Aquila – and false warnings are as bad as no warnings
Of all the natural disasters that mankind faces, earthquakes are the least susceptible to prediction. Hurricanes and tropical storms can be tracked by satellites; tsunamis, sometimes, can be detected while they are far enough from land to give people time to get to higher ground. Even volcanoes frequently telegraph an upcoming eruption: in the months ahead of Mount St Helens’s eruption in 1980, the mountain itself swelled and bulged as magma gathered below the surface. But despite hundreds of years of old wives’ tales, and, more recently, serious research, even the most devastating earthquakes are pretty much as unpredictable in 2012 as they were in prehistoric times.
Which makes it all the stranger that, in L’Aquila, central Italy, six scientists and a government official have been convicted of manslaughter and jailed for six years for giving “inadequate” assessment of the risks ahead of a devastating quake in 2009 that killed 309 people in the city.
The prosecution’s case is that the group gave “generic and ineffective … incomplete, imprecise, and contradictory information” about the risks of an earthquake. They claim that 29 of the dead in L’Aquila intended to leave the city, after it was rocked by dozens of small tremors in the days before the quake, but were persuaded to stay in their homes by a statement given by Bernardo De Bernardinis, the government official, which said that “the scientific community tells me there is no danger because there is an ongoing discharge of energy” from the small tremors. That was wrong: there was a danger. But the scientists who advised him had said something different – that there was an increased risk of a major earthquake in the region, in the light of those small tremors, but that it was impossible to say anything more precise than that about the time or the place. That information may have been “generic and ineffective”, but it was also the most that could be credibly said. It is true that before about half of major earthquakes, there is a series of smaller tremors such as those felt in L’Aquila. But while that sounds important with the benefit of hindsight, this fact has almost no predictive power: only about one time in 50 will a series of minor tremors herald a big one.
Other methods have been put forward as possible means of predicting earthquakes. Research is continuing into seismic anisotropy, which measures the stress in rocks. It is also suggested that radon gas is released ahead of a large quake. But none of these possibilities has been shown to work with any reliability, and a wildly oversensitive earthquake detector is as bad as none at all. A series of false alarms would disrupt everyday life, and instil a sense of fire-drill apathy when the real thing comes along.
This is an attack on scientific independence that could have far-reaching effects. As Alan Leshner, the CEO of the American Academy for the Advancement of Science, said in an open letter to the president of Italy: “Years of research, much of it conducted by distinguished seismologists in your own country, have demonstrated that there is no accepted scientific method for earthquake prediction that can be reliably used to warn citizens of an impending disaster.”
Seismological science may not be able to predict precisely when and where an earthquake will strike, but it can highlight periods and areas of high risk, and offer ways of reducing that risk and mitigating damage, like well-designed and enforced building codes in earthquake zones. Italy’s apparent decision to blame seismologists for an act of nature has the potential to drive an entire scientific community out of precisely the country where its work is most needed.
Unfortunately, it is also a country which takes scientific evidence less seriously than many others in its national discourse, one in which a major murder investigation debated seriously whether or not the suspect Amanda Knox was influenced by Satan. Local coverage of the disaster has focused on a man called Gioacchino Giuliani, a technician in a physics lab. He had been warning locals that a quake was coming; and if he could, the papers asked, why couldn’t the scientists? But his prediction, using the radon gas method discussed above, was out by a week and several miles. More importantly, he was probably just lucky: he had made at least two false alarms, and it seems highly implausible to say that he has single-handedly solved the problem of earthquake prediction that has evaded science for centuries.
There are many things that could have been done better in the build-up to L’Aquila. Thomas Jordan, a professor of earth sciences writing in New Scientist, points out that Italy (together with every other seismically active country) has no good system of short-term forecasts, to inform the public when the risk of quakes has gone up – the overall risk will always remain low, but making the information available would allow people to decide for themselves how to deal with it. That is the sort of sensible lesson that can be learnt from the tragedy. Locking up a group of scientists for not doing the impossible is both stupid and counterproductive.