The Risks of Risk Communication (for Italian Earthquakes)


The Basic Facts

In October 2008, the city of L’Aquila in Italy began experiencing earth tremors. Given that the city has been pretty much destroyed by earthquakes twice in the past, this was a matter of some concern. For the next six months the tremors continued. On March 31 the National Committee for the Prediction and Prevention of Major risks had a meeting, and a civil service spokesman re-assured the public that there was no immediate danger. Within a week, more than 300 people were killed when a major earthquake struck.

Seven members of the National Committee were charged with manslaughter for providing the public with information that was “inexact, incomplete and contradictory”, and on Monday this week they were sentenced to jail terms of six years.  There are many misleading summaries of this case available, perhaps because of the tangential prosecution and defence cases. The defence, both in court and in public maintained that it was not reasonable to expect scientists to predict the timing of an earthquake. However, that isn’t what the prosecution was alleging. The prosecution case was that the scientists didn’t communicate the risk appropriately. According to the prosecution, at least 29 of the victims stayed in an unsafe situation due to receiving misleading information about the risk they faced.

Two news stories with accurate portrayal:

There are three underlying questions here:

1) Can you do risk estimation for an earthquake?
2) How should you communicate risk information of this sort?
3) Should you get six years in jail if you do either of these incorrectly?

Risk Estimation for Earthquakes

Unlike most infrequent high-consequence events, the risk of an earthquake in certain areas does build up over time. So while it is nonsense to say that we are “overdue” for a big storm, a flood, or a stock-market crash, it does actually make some sense to say that an area is overdue for an earthquake. These are still low probabilities though – for example, Southern California is waiting for the next big one, meaning that there’s around a 2% chance of a major quake in the next thirty years.

Most earthquake science is focussed on modelling what’s likely to happen during an earthquake, rather than when the earthquake will come. This make sense, because the most effective protective measures are long-term anyway:  Good building design; removing or protecting buildings built before the modern building codes; and teaching people appropriate earthquake behaviour. By understanding the range of scenarios that are likely or possible, we can put appropriate protection in place.

As far as short-term prediction goes, big earthquakes do often have fore-shocks – smaller movements leading up to the highest energy event. These can, on a scale of a few minutes to a couple of days, give warning of increased risk. There is a lot of uncertainty involved, and it’s an area where more research and more computer power may be able to improve predictions in future. At the moment, it’s akin to clouds as a predictor of rain. You aren’t totally safe if the sky is clear, and seeing clouds doesn’t tell you that it’s going to rain, but looking at the sky does help you determine the odds.

The Southern California Earthquake Center has good general information on earthquake modelling, as well as a handy guide to living in an earthquake-prone area.

Risk Communication

Risk communication is a whole scientific field in its own right, with a compelling message that it isn’t enough to simply tell the truth about risk, you have to tell it in a way that people can make sense of. An Australian earthquake expert Professor Paul Somerville said that the Italian team had a case to answer because of the way they communicated. As far as I can tell from the news reports though, his answer is that the scientists should stick to reporting numbers and let society do the interpretation. This isn’t what the research on risk communication suggests.

The archetypical example is doctors telling patients about the risks of treatment. Simply quoting numbers like one in a thousand or one in ten-thousand patients experiencing a side-effect is meaningless without context. Patients can’t make useful sense of these numbers. Comparisons instead or as well are often very useful. “This drug is about as dangerous as panadol, and much safer than doing nothing”; or “There is a small chance that this drug will make things worse – about the same chance as you being in a car accident in the next year”.

One consistent result in risk communication research is that deliberately being inaccurate in order to reassure people doesn’t work. The situation in Italy was complicated by scare-mongering by various parties, including one seismic technician giving warnings through a megaphone. The scientists rightly thought that it was important for people to have a realistic view of the risk. With hindsight, it’s easy to put better words in their mouths such as “The tremors are a sign of increased risk, but they don’t tell us whether or not a big earthquake is about to happen. Citizens should, as always, make sure that they have followed the steps in the earthquake preparedness booklet, and know what to do if an earthquake does happen”.

The work of Professor Terje Aven at University of Stavenger is a good starting point for reading about risk and risk communication.

Jail for Poor Risk Communication?

Personally, I think that not being able to properly communicate the risk of a major hazard is a pretty big deal when your job description is to communicate the risk of major hazards. The committee deserved to be dragged over the proverbial coals whether or not the earthquake happened.

Drawing a causal link between their inept communication and people dieing is another thing altogether. It’s easy to say afterwards that person X would not have stayed in their shaky house if they’d known the true risk. That’s rather hard to prove though, given that people were living in poor housing in an earthquake zone for months and years. Yes, some people might have skipped town for a couple of days, but that wouldn’t have been a rational response to the risk. Those same people would still have been killed if the earthquake happened a week later, or two weeks later, or a month later.

Essentially, the court has found that a combination of proper risk communication, irrational response, and good luck, would have saved lives, therefore the scientists are at fault. Hopefully, they win their appeal. I don’t think that this will have a chilling effect however. I hope and believe that this will make more scientists realise that communication is an important part of their role, and requires as much care and attention as the research itself.

Other Links

The Professor Paul Somerville interview is here.

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2 Comments on “The Risks of Risk Communication (for Italian Earthquakes)”

  1. I just finished listening to this on the podcast, and it is the first time something has irritated me enough to go to the website to comment on it.

    (Full disclosure: I am doing a PhD in volcanology, and some of my colleagues in the lab know the scientists personally.)

    Firstly, I have to correct you about earthquake prediction. From a scientific point of view, the foreshocks are a complete red herring. Seismic swarms are common in tectonically active regions; sometimes they coincide with large earthquakes and sometimes they don’t. Their occurrence is not correlated in any meaningful way, and therefore seismic swarms should be ignored when calculating the short-term risk of a large earthquake. You use the analogy of looking for clouds to predict rain; I’d argue it is more like looking to see if the cows are sat down to predict rain. Also, the term ‘overdue for an earthquake’ tends to irk geologists slightly. While average recurrence times can give you an idea of how often large earthquakes happen, there is still far too much variability in the time between one earthquake and the next for the time since the last earthquake to be much use in predicting the short term probability. If you accept that there was no scientific reason to suggest an increased risk of a big earthquake, then the manslaughter charges become self-evidently ridiculous. No matter how good the communication was between the scientists and the public was, those 29 people still would have died. There was no scientific evidence to suggest they should have evacuated.

    While I agree with much of what you say about communicating risk, and I agree that this was an example of it done poorly, I take issue with your closing remarks. You say the job description of those scientists was to communicate risk? No, their job was to advise the government on the risk, and the did this in good faith and to the best of their (and anybody else’s) ability. The minutes of the meeting held in l’Aquila show that the scientists’ conclusion was that there was “no elevated risk”. Scientifically this is completely uncontroversial. I have heard (albeit anecdotally) that Italian scientists are under a lot of pressure politically to not discuss these issues in public. I don’t think it’s coincidence that the spokesman of the commission, and the one who made all the controversial comments, was not a scientist but a civil servant.

    I agree with you that the solution is better risk communication and more education, but this verdict is going to make things far more difficult. You dismiss the chilling effect of this court case with barely a second thought. How many scientists do you really think would be willing to provide advice, either in private to governments or to the public at large, if they can be held criminally responsible for any subsequent disaster (no matter how unexpected)? Already, the top three scientists on the Italian national commission for natural disasters have resigned.

    Here is what the AGU (American Geophysicists Union, probably the largest and most influential geoscience body and despite its name pretty international) had to say about it:

    “For scientists to be effective, they must be able to make good faith efforts to present the results of their research without the risk of prosecution. Outcomes such as the one seen in Italy could ultimately discourage scientists from advising their governments, from communicating the results of their research to the public, or even from studying and working in various fields of science.”

    Finally, here what is IAVCEI (International Association for Volcanology and Chemistry of the Earth’s Interior, the biggest volcanological association, who have to deal with much the same issues) have to say:

    “This conviction sets a terrible international precedent. It should cause all scientists employed in monitoring and advising government and civil authorities on potential natural hazards grave concern about the advice they give, and to cover all possibilities in great detail. There is also a flip side to this. What would have happened if the convicted scientists had forecast the worst-case scenario before the l’Aquila disaster, resulting in the evacuation of a half a million people of more in the region, but then nothing happened? Would they then also have been charged with providing misleading information and causing unnecessary costs to government and community?

    “Natural disasters are bad news for everyone – affected communities, governments, civil authorities, industry and the scientific community. The real concern now for the scientific community is that civil authorities could try to deflect attention from themselves and the relief effort after a crisis by playing the “blame game” and taking legal action against scientists for “providing inaccurate information”.”

    • ajrae says:

      Gareth,
      Thanks for taking the time to make a detailed response. I just want to respond to a couple of the points you made:

      1) I don’t think makes sense to say that someone’s job is to advise the government, but not to communicate risk. Advice is
      a form of communication – and in this case the committee clearly had both a public policy role AND a public communication role. Advising
      the government arguably requires a higher degree of competence in communicating risk.

      I don’t think anyone is doing anyone any favours by conflating the issues of communicating risk and assessing risk. The scientists have not been
      accused of being wrong, or even being uncertain. As far as I can tell from secondary sources (I don’t speak Italian) the public announcement was not
      consistent with what they had discussed as a committee. The quotes you’ve given are from organisations pushing the “they didn’t predict the earthquake” interpretation
      which is perpetuating mis-information. I agree that if this is the message that comes out of this, it will have a chilling effect, but it will be the scientific community
      responsible for scaring themselves, not the prosecution.

      2) I’m not going to win an argument about earthquakes with a volcanologist. My understanding of the models is that both periodicity and foreshocks both have weak predictive power (contrasting weak
      with “none”, not with “strong”). Are you saying that there is a consensus view that this isn’t the case, or are you saying that its a matter of scientific debate whether this is the case?

      3) I think the manslaughter charge is ridiculuous even without accepting that there was no reason to believe in an increased risk. If there was an increased risk, it would apply over months, not
      over a few days, and the level of hearsay/mindreading/assumption necessary to draw a link between the communication and deaths is huge. If I wasn’t clear about this in the report, I apologise. There’s a lot of poorly directed outrage about this case, and it is unnecessary. There’s plenty to work with without misrepresenting what actually happened. (For clarity, I’m not accusing you of this – just some of the reporting and public letters).

      I’d appreciate your further thoughts on these. If I’m wrong about (2) particularly, I’ll put out a correction. Citable sources would be very helpful for this.


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