L’Aquila convictions about science communication, not about quake prediction - 23/10/2012

The manslaughter conviction of six scientists and a government official in the wake of the magnitude 6.3 L’Aquila earthquake in Italy in 2009 is a complex matter involving legal, scientific, emotional and political aspects. It is also concerned with a very specific set of circumstances.

We understand that the court case was not about failing to predict an earthquake. Most people understand this is not possible with current scientific knowledge. There are no proven precursory signs such as gas measurement, micro-earthquakes, animal behaviour, electrical phenomena, or lunar phenomena that can predict earthquakes. Despite decades of research into earthquake processes, the ability to predict earthquakes remains elusive.

The Italian case is really about the ineffective communication of science. In this instance, the scientists and government official were found to be deficient in the way they communicated the state of scientific knowledge and the possible threat of a large damaging earthquake.

The communication of risk and uncertainty is a challenging area for scientists. But to suggest that repeated small earthquakes in the area of L’Aquila were favourable because they unloaded seismic stress and reduced the chance of a big quake was unwise in our view. This, and other comments from officials, apparently inhibited many people from taking actions that might have saved their lives.

Equally, 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.

It is difficult to make any direct comparisons between L’Aquila and what happens in New Zealand. The roles and responsibilities of scientists and government officials are different in the two countries. However, the case does provide lessons about the communication of science and earthquake risks to officials and the public.

The most scientists can do is to estimate the probability of an earthquake occurring in a given region over a certain time frame 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.

GNS Science endorses the need for scientists to communicate meaningful information about natural hazards and probabilistic information to government agencies and the public. In this regard, for example, we update our aftershock probabilities for the Canterbury region on a monthly basis.

In relation to the Canterbury earthquake sequence, over the past two years GNS Science has undertaken hundreds of communications with a wide range of stakeholders via public seminars, briefings to government agencies, written reports, video and Youtube clips, plus many communications with the print and electronic media.

It is worth noting that in the past 60 years in Italy, only six of 26 major earthquakes have been preceded by foreshocks and many earthquake swarms have occurred without subsequent large earthquakes.

As foreshocks are usually not any different to ‘background’ earthquake activity, it is impossible to make a diagnosis that they are precursors to a major earthquake. Worldwide, most major earthquakes do not have precursory foreshocks.

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.

There is a need for balanced information so government agencies and the public have the ability to make informed decisions about their actions.

Part of GNS Science’s core purpose, established by the Government, is to increase New Zealand’s resilience to natural hazards and reduce risks from these hazards. As its role requires, GNS Science will continue to communicate measured and meaningful information about natural hazards to government agencies and to the public.