Una parodia della giustizia?

Damage caused by the L’ Aquila earthquake of 6 April 2009. (credit: Reuters)

Lying above a destructive plate margin, albeit a small one, Italy is prone to earthquakes. Seismometers detect a great many of low magnitude that no one notices and that do no obvious damage to buildings. From 2006 to autumn 2008 the Abruzzo region on the eastern flank of the Appenine mountains of central Italy experienced a background of one low-magnitude tremor every day (Papadopoulos, G.A. et al. 2010. Strong foreshock signal preceding the L’Aquila (Italy) earthquake (Mw 6.3) of 6 April 2009. Natural Hazards and Earth System Sciences, v. 10, p. 19-24). In the following 6 months the rate more than doubled but the epicentres continued to be almost randomly situated. Things changed dramatically in the 10 days following 27 March 2009: the pace increased to twenty times the normal ‘background’ and epicentres clustered directly beneath the regional capital L’ Aquila (population 73 thousand) close to a known fault line. At 3.32 am on 6 April 2009 the Paganica fault failed less than 10 km below L’ Aquila, directing most of the Magnitude 6.3 energy at the town. This was the deadliest earthquake in Italy for three decades; 308 people died 1500 were injured and 40 thousand found themselves homeless. Silvio Berlusconi, not a man to flinch from controversy, commented on German TV about the homeless, ‘Of course, their current lodgings are a bit temporary. But they should see it like a weekend of camping’.

English: Silvio Berlusconi in a meeting with J...
Former Italian President Silvio Berlusconi (credit: Wikipedia)

L’ Aquila has a dismal history of seismic damage, having been devastated before: 7 times since the 14th century. Having grown on a foundation of lake-bed sediments, notorious for amplifying ground movements, the city was clearly in a high-risk status in much the same manner as Mexico City. Shaken several times before and built with no regard to seismicity, much of L’ Aquila’s centuries-old building stock was incapable of resisting the event of 6 April 2009: up to 11 thousand building were damaged, some collapsing completely.

Not only was the earthquake preceded by an increasing pace of foreshocks, but many local people reported strange ‘earth lights’ during the months beforehand (Fidani, C. The earthquake lights (EQL) of the 6 April 2009 Aquila earthquake, in Central Italy.Natural Hazards and Earth System Sciences, v. 10, p. 967-978). In fact, so many sightings were made that plans have been outlined for a CCTV monitoring network in rural areas.

So, this disaster was not short of signs that all was not well in Abruzzo, in a seismic sense: historical precedent; poor urban siting; foreshocks and oddities that have come to be associated with impending energy release. But was this litany sufficient to predict the place, date, and magnitude of what was coming? Plate tectonics, local structural geology and worldwide seismicity allow geophysicists to assess risk from earthquakes in the same way as hydrologists can outline flood-prone areas: literally on flood plains. Yet there are few if any records of a devastating earthquake having been predicted anywhere with sufficient accuracy to allow evacuation and mitigation of death and injury. That is despite the fact that teams of seismologists in the western US, Japan, Italy and several other well-off countries continually monitor seismic events even with a power many orders of magnitude less than those which kill or injure. Such bodies are faced with a dreadful choice in the face of evidence like that summarised above: warn tens of thousands to evacuate, organise such an exodus in a few days and prepare accommodation for them, or advise that similar seismic escalations rarely lead to massive damage with an estimate of the probability of risk. Both choices are guesswork for there are no rigorous equations that spell ‘doom’ or ‘all clear’ from such data. Earthquakes are not rainstorms or hurricanes, as 250 thousand dead people on the shores of the Indian Ocean bear grim witness.

Despite broad knowledge of the deep uncertainty associated with earthquakes and volcanic eruptions – no longer privy to specialist scientists these days, even in the least developed parts of the world – the Italian authorities saw fit to prosecute six earth scientists and a public official for multiple manslaughter.  Because they provided “inaccurate, incomplete and contradictory” information about what might have been the aftermath of tremors felt ahead of 6 April 2009 earthquake, a regional court sentenced all of them to six years in prison – two years more than even the prosecution demanded – and they are to pay the equivalent of £6.7 million in compensation. This was not a jury verdict, but the decision of a single judge, Marco Billi. No scientist, even one poring over data from the Large Hadron Collider in search of the Higgs boson, would every claim that what they report is perfectly accurate, complete and incontrovertible. The L’Aquila Seven never said they were certain that no earthquake would ensue, and the city’s people were well aware of what risk they faced in much the same way that Neapolitans living on the slopes of Vesuvius know that one day they may be incinerated.

This is a travesty of justice so bizarre that one must look to the famous adage of Roman Law: qui bono? Certainly not the victims and their mourners, and definitely not science because any sensible Italian geophysicist will in future simply play dumb. There is already a huge world wide outcry, not just from outraged scientists.

Added 25 October 2012: The 12 October issue of Science carried a lengthy summary of proceedings early in the trial (Cartlidge, E. 2012. Aftershocks in the courtroom. Science, v. 338, p. 185-188). Read Nature‘s editorial on the L’ Aquila verdict here and further comment.