On October 22, 2012, Italian judge Marco Billi announced a verdict convicting seven men, six prominent scientists and one civil servant, of multiple manslaughter in connection with their public comments before the devastating 2009 L’Aquila earthquake. If the verdict and sentence survive appellate review, each man will face six years in prison and liability for nearly $12 million in damages.
While a complete analysis of the verdict’s implications must await the publication of Judge Billi’s reasoning, international observers like the American Geophysical Union (“AGU”) have already voiced concerns over the verdict’s possible chilling effect on scientific discourse. From the perspective of the L’Aquila plaintiffs, however, that criticism may seem inapposite. They arguably seek more and clearer communication of scientific knowledge.
During the spring of 2009, a series of tremors in the earthquake-prone Abruzzo region caused widespread unease among L’Aquila’s residents. Seeking calm, Italy’s Department of Civil Protection convened a March 31, 2009, meeting of its National Commission for the Forecast and Prevention of Major Risks in L’Aquila to provide residents “with all the information available to the scientific community about the seismic activity of recent weeks.” All seven defendants were members of the Commission.
Inside the meeting, the Commission told journalists that although absolute odds of a large-scale earthquake were low, in such a risk-prone area “the possibility [could not] be totally excluded.” Outside the meeting, two defendants joined L’Aquila’s mayor for a press conference. When a local journalist commented, “So we should have a nice glass of wine,” defendant Bernardo De Bernardinis, present in his capacity as the vice-president of Italy’s Civil Protection Agency’s technical department, responded “Absolutely.” He called the situation “normal,” suggested there was “no danger,” and stated, “the scientific community continues to assure me that, to the contrary, it’s a favorable situation because [the tremors amounted to a beneficial] continuous discharge of energy.”
One week later, on the night of April 5-6, a strong tremor around 11 p.m. preceded the devastating 6.3-magnitude 3:32 a.m. earthquake. 20,000 buildings collapsed in L’Aquila and its surrounding towns. 309 people died, more than 1,500 were injured, and 65,000 were temporarily displaced.
One plaintiff, Vincenzo Vittorini, recalled how responses to the 11 p.m. tremor diverged along generational lines. “That night, all the old people in L’Aquila, after the first shock, went outside and stayed outside for the rest of the night,” he said. “Those of us who are used to using the Internet, television, science — we stayed inside.” According to commentators, during the trial Judge Billi “recogni[z]ed a direct causal link between the conduct of the convicted and the decision of some … victims to stay inside. Specifically, he recognised a causal link for 29 deaths and four injured people.”
What duties did the Commission owe citizens, and who should bear the costs?
Public prosecutor Fabio Picuti maintains that the case does not turn on defendants’ inability to predict the quake. In an interview with Nature writer Stephen S. Hall, Picuti stated, “I’m not crazy … I know they can’t predict earthquakes. The basis of the charges is not that they didn’t predict the earthquake. As functionaries of the state, they had certain duties imposed by law: to evaluate and characterize the risks that were present in L’Aquila.”
According to plaintiffs’ attorney Simona Giannangeli, De Bernardinis’s press conference remarks gave the public a false sense of security. “It was repeated almost like a mantra: the more tremors, the less danger,” she commented.
Unfortunately, the “more tremors, less danger” mantra was simply wrong. A 1988 study of seismic swarms in Italy concluded medium-sized shocks like the 11 p.m. tremor are followed within several days by major earthquakes about 2% of the time. Here, the difference between absolute and relative probability becomes important. Any specific prediction of an earthquake in such a situation would have a 98% chance of resulting in a false alarm, but the Italian Commission apparently failed to communicate to citizens that the relative risk of an earthquake in the week following a shock might be anywhere from 100 to 1,000 times higher than during a normal week.
Do members of a public commission have a duty to highlight such information? The Commission might have a sufficiently public character to warrant an exception to the “no duty to warn” baseline. However, the Commission apparently did accurately inform journalists that a small absolute risk could not be ruled out.
The key duty question thus seems to be whether the Commission members’ status as technical experts created a duty to comprehend and communicate the relatively high risk of a large earthquake shortly after a significant tremor. The verdict suggests Judge Billi recognized such a duty. Supporters of the verdict may argue that citizens have a right to know the relative risks so that they may make personal decisions in a fully-informed manner. The verdict’s detractors, on the other hand, might prefer preserving public experts’ discretion. Lay overestimation of the absolute-terms meaning of 100-fold increases in relative risk could spark episodes of mass panic.
Critics of Judge Billi’s ruling might also argue that citizens who chose to remain in their homes after the 11 p.m. tremor should bear the costs of their decisions. This argument would point to citizens as the “least cost avoiders.” However, supporters of the ruling may reply that without full knowledge of the relative risks citizens had no opportunity to accurately weigh the possible consequences. Arguably, the Commission’s calming words caused many of L’Aquila’s citizens to eschew the traditional precaution of exiting their homes and sleeping outdoors after the 11 p.m. tremor.
 All factual details and quotations originally appeared in Stephen S. Hall, Scientists on Trial: At Fault?, Nature (Sept. 14, 2011), http://www.nature.com/news/2011/110914/full/477264a.html.
 Valentina Koschatzky, Scientists Found Guilty for L’Aquila Earthquake Deaths … but Why?, The Conversation (Oct. 24, 2012, 6:34 AEST), http://theconversation.edu.au/scientists-found-guilty-for-laquila-earthquake-deaths-but-why-10292.