IN THE early hours of 6 April 2009, a in central Italy, killing 308 people and leaving thousands homeless. This week six Italian scientists stand trial on manslaughter charges for their alleged miscommunication of the seismic risk.
The case has become a cause c茅l猫bre among scientists. When news of the prosecutions broke last year, the reaction was furious. The indictments seemed to blame the scientists for not warning of an impending earthquake even though accurate short-term prediction of large earthquakes is not yet possible. Scientific societies from around the world wrote letters of protest to Italy鈥檚 president and thousands added their signature.
Court documents later filed by the prosecution attempted to recast the accusations not as sins of omission but as acts of commission. The scientists were charged with conducting a risk assessment that was 鈥済eneric and ineffective鈥�, providing civil authorities and the public with 鈥渋ncomplete, imprecise, and contradictory information about the nature, causes, and future developments of the seismic hazards鈥�, and characterising the seismic swarm that affected L鈥橝quila for about three months before the main shock as 鈥渁 normal geological phenomenon鈥�.
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Did the scientists do anything wrong? The facts of the case are complex. Seismic activity in the L鈥橝quila area increased in January 2009, prompting school evacuations and other preparedness measures. Media coverage was inflamed by a series of earthquake predictions issued by Gioacchino Giuliani, a local man who worked as technician in a physics laboratory. These predictions had no official validity but were widely reported. At least two of the predictions were false alarms. No evidence indicates that Giuliani transmitted to the public or any civil authority a valid prediction of the main shock.
In response, government scientists stated correctly that there was no validated method for earthquake prediction, that earthquake swarms were common in this part of Italy, and that the probability of larger earthquakes remained small.
But they did not dispel public concern, and on 31 March, Italy鈥檚 Department of Civil Protection (DCP) hastily convened a meeting of its in L鈥橝quila. That meeting, and the press conference that followed, were crucial.
The meeting concluded: 鈥淭here is no reason to say that a sequence of small-magnitude events can be considered a predictor of a strong event.鈥� This statement was scientifically correct.
At the later press conference, however, DCP vice-president Bernardo De Bernardinis, who is not a seismologist nor a member of the Major Hazards Committee, said: 鈥淭he scientific community tells us there is no danger, because there is an ongoing discharge of energy. The situation looks favourable.鈥� This statement was not scientifically correct. Seismic activity continued, and a few days later the main shock occurred. Nearly everyone in L鈥橝quila, including the prosecutor, lost relatives or friends. De Bernadinis and six scientists were indicted for manslaughter.
I can see no merit in prosecuting public servants who were trying in good faith to protect the public under chaotic circumstances. With hindsight their failure to highlight the hazard may be regrettable, but the inactions of a stressed risk-advisory system can hardly be construed as criminal acts on the part of individual scientists. One can only hope that judicial sanity will prevail.
鈥淭he inactions of a stressed risk-advisory system should not be seen as criminal acts on the part of scientists鈥�
Yet the situation provides an opportunity to think through some larger issues that will surely recur for scientists involved in hazard management.
The Italian scientists were trapped by a simple yes-or-no question: 鈥淲ill we be hit by a damaging earthquake?鈥� This was not surprising given Giuliani鈥檚 alarms, but it was not one they could answer conclusively. From what they knew a week before the earthquake, a big shock was not very likely: the probability of a false alarm (if an alarm were raised) exceeded the probability of a failure-to-predict (if an alarm were not cast) by a factor of more than 100. Even so, seismic activity had increased the probability of a large earthquake by a significant factor, perhaps as much as 100-fold, above the long-term average.
Distracted by Giuliani鈥檚 predictions, the authorities did not emphasise this increase in hazard, nor did they focus on advising the people of L鈥橝quila about preparatory measures warranted by the seismic crisis. Instead, they made reassuring statements that were widely interpreted to be categorical.
A few weeks after the L鈥橝quila disaster, the Italian government appointed an international panel of experts, which I chaired, to suggest guidelines for improving earthquake forecasting in Italy. Our report reaffirmed that there is no known method to predict earthquakes with high probability.
It also addressed how short-term forecasts 鈥� in which the probabilities of large shocks may change but are invariably low 鈥� could be publicly utilised. Our review found the Italian system wanting in this regard, but we could not point to a country in which earthquake forecasting was done much better.
All of us who face high seismic risks can learn lessons from L鈥橝quila. Among them is the need to separate the role of science advisors, whose job is to provide objective information about natural hazards, with that of civil decision-makers who must weigh the benefits of protective actions against the costs of false alarms. One of the key lessons of the L鈥橝quila prosecution is that misconstruing these roles leads to trouble.
