Earthquake scientists on trial

At present, it is not possible for scientists to accurately predict the time, location or strength of earthquakes, nor to tell if a swarm of small quakes are foreshocks to a larger event or just small earthquakes. It seems incredible, then, that six science experts were convicted of manslaughter following the deaths of 309 people in the Italian city of L’Aquila caused by the 6.3 magnitude (Mw) earthquake on 6 April 2009.

Prior to the earthquake, the area experienced a seismic swarm – thousands of small earthquakes. In March 2009, the Civil Protection Department called in experts – six geophysicists and a government official – to assess the situation and discuss the risks with local officials.

After the meeting, the group held a press conference. One of the experts, Professor Enzo Boschi, president of Italy’s National Institute of Geophysics and Volcanology (NIGV), was reportedly asked if the seismic rumblings could flatten the city as in 1703. He is recorded as replying that it was “unlikely but the possibility cannot be totally excluded”. Dr Bernardo De Bernardinis, a floods expert, is reported as saying that the on-going tremors were “certainly normal” and presented “no danger”. He is reported as saying that the tremors were a release of energy that could safeguard the region. However, two of the scientists at the meeting said they disputed this strongly.

These reassurances led some L’Aquila residents to believe there was no imminent danger – the victims remained indoors during the 6.3 earthquake.

Arrested for manslaughter

The seven experts were charged with manslaughter and served with a civil suit seeking more than $30 million in damages. The prosecution alleged that the group provided “generic, ineffective, incomplete, imprecise and contradictory information about the nature, causes and future developments of the seismic hazards in question”. The public prosecutor said that he understood the scientists cannot predict earthquakes, but “as functionaries of the state, they had certain duties imposed by law: to evaluate and characterise the risks that were present in L’Aquila”.

International support for the scientists

Before the trial, the NIGV published a letter of support for the scientists signed by over 5,000 researchers worldwide, including 81 New Zealanders. Despite this international protest, the trial of the seven accused began in late September 2011.

Guilty verdict

On 22 October 2012, the seven experts were convicted of manslaughter, barred from holding any official position in the future, fined more than $NZ14 million and sentenced to 6 years in prison – 2 more years than the prosecutor had requested.

Most scientists around the world were quick to condemn the verdict, but there were some notable and thoughtful exceptions. Northland-based Dr Chris Buckley, formerly of California State University’s seismic laboratory, said he thought the scientists should be held accountable in some manner as, at least in one case, they had “exceeded their scientific knowledge” in an attempt to reassure the public about the on-going tremors in the region. In an interview with Radio New Zealand, Dr Buckley said, “There is no record of anyone ever predicting an earthquake, and if that is true, then it means people have [also] never been successful in predicting a non-earthquake.”

However, many scientists felt that the punishment didn’t fit the crime or that the case was misdirected. A statement issued by GNS Science in Lower Hutt following the verdict points out: “The L’Aquila area had a known history of earthquake activity, and government officials could arguably have done more to prepare city infrastructure and the population for a large earthquake through measures such as setting appropriate building standards.”

Italian-born quake engineer Stefano Pampanin, Professor of Structural Design and Earthquake Engineering at the University of Canterbury, agrees. In an interview with The Press, he said he was ‘‘disappointed and frustrated’’ to hear of the court’s verdict.

The need for effective communication

Dr Buckley said the issue was one of science communication – the scientists had failed to communicate the uncertainty of whether there could be a major earthquake or not. “I think scientists should be very careful about making statements that are, from a scientific viewpoint, not supportable.”

GNS Science noted the L’Aquila case provided a lesson about the communication of science and earthquake risks. Its statement read: “The most scientists can do is to estimate the probability of an earthquake occurring in a given region over a certain timeframe such as months, a year or longer. However, because natural events are inherently unpredictable, the limitations on the meaning of these probabilities need to be communicated clearly to the public.

“Scientists must weigh up the evidence carefully and be cautious about the possibility of saying too little and delivering a false sense of security that could cause complacency or delivering a false alarm that could cause panic.”

Verdict overturned

In November 2014, an Italian appeals court acquitted six of the experts. Bernardo De Bernardinis received a 2-year sentence for causing some but not all of the deaths. The appellate judges criticised the indictment for its reliance on a purely regulatory measure of guilt. The court said the men should have been judged on how well they complied with the science of the time.

Science thinking has changed since the L’Aquila earthquake. Italian seismologist Francesco Mulargia said, “Ninety-nine times out of 100, a swarm won’t lead to a major earthquake and so it is not a deterministic precursor. But it is still an important warning sign.”

Some people say they can predict earthquakes. However, at GeoNet we stick to our knitting: we are a science organisation and base our work on things we can observe and measure. At present there is no scientific way to accurately and reliably predict when and where a big earthquake is going to happen.

GeoNet

Forecasting New Zealand earthquakes

GeoNet, a collaboration between the Earthquake Commission and GNS Science, has information about earthquake forecasts on its website. The forecasts it produces are not predictions – predictions involve specific times and locations. The forecasts help infrastructure managers and other officials focus efforts and plans after events like the 2010 Christchurch and 2016 Kaikoura earthquakes. They also give people living in areas affected by aftershocks an indication of the range and probability of future aftershocks.