No. Whatever it is this time, it really can’t predict earthquakes.

A post by Chris RowanOne of the courses I’m teaching each semester here in Kent is called ‘Earth Dynamics’: an introductory-level geology course aimed at the broader undergraduate population. With that in mind, I try to identify and highlight areas where the topic at hand may intersect with the everyday lives of my students. Thus when, last week, we covered earthquakes, I had to address the thorny topic of earthquake prediction. I’ve covered this topic many, many times here on the blog, which has probably not only emphasised to me the importance of covering it in class, but also made me perhaps a little more ranty about it than is healthy. My rant can be summarised thusly:

  • It is important to distinguish between specific, short-term predictions (‘that fault will rupture in a magnitude 7.5 earthquake next Friday’), and general, probabilistic, long-term predictions, or forecasts (‘this area has a 1 in 4 chance of experiencing a magnitude 7 or greater earthquake in the next 30 years’). We presently have no ability – or inkling of an ability – with regards to the former. Even with the latter, we face severe limitations due to the lack of a long-term earthquake record in most regions, but it is currently the only game in town.

  • Don’t believe anyone who claims they can accurately predict earthquakes over the short-term. These people are at best extremely misguided, and at worst frauds and charlatans. The only way that they are successful is to make loose ‘predictions’ in a seismically active area and adopt very broad criteria for ‘success’ (‘That magnitude 5 200 km from where I said there’d be a magnitude 8 was totally right. I’m a genius!’). People claiming the prospect of an even bigger shock in the aftermath of a big quake, such as seems to have been the case for last week’s destructive M 7.2 in the Philippines, operate from a similar playbook.

  • Quake prediction folks  - this is you. And you should be taken about as seriously. Source

    Folks producing daily earthquake predictions – this is you. And you should be taken about as seriously. Source

  • When you read headlines with the form ‘Can x predict earthquakes?’, the answer is always ‘NO’. For any value of x, be it planetary alignments, animal behaviour, weather, foreshock patterns, radon gas emissions, ionospheric disturbances, low frequency electromagnetic signals, anything, the answer is still ‘NO’.

Sadly, such headlines are all-too-common, as NBC proved this morning:

Yes. Yes it is.

Yes. Yes it is.

By this stage, my response should not surprise you:

Over at Deep Sea News, Craig deconstructs this particular example quite nicely, but the underlying problem is always the same. The association is always post-hoc: these ‘precursor’ events are only claimed as such when people look backwards after a large earthquake has already occurred – and a more detailed look always reveals a huge problem with false positives (signal, but no large earthquake) and false negatives (no signal, but a large earthquake anyway). Thus, even if the weirdly behaving animals, or infra-red anomalies in the atmosphere, or strange foreshock patterns, are actually connected to an imminent destructive earthquake, we have no understanding of how and why, so we currently have no way of systematically using future observations to make future predictions. The only thing more annoying than the uncritical discussion of claimed earthquake precursors in the media is the assumption that, if it is valid, it’s then an easy step to building a short-term earthquake warning system. It is not.

Despite my obviously hardline stance on these matters, I am happy to concede that all this may change in the future. It’s certainly possible that we can pick up valid signals associated with incipient fault rupture at depth, and we may eventually understand the processes that generate them enough to – potentially – weed out the false positives well enough to make them useful for shorter term forecasting. But I wouldn’t hold your breath – earthquake scientists have been looking and hoping for such tools for decades, and even the ones that have appeared promising initially have failed to hold up to scrutiny in the long run.

Not only can oarfish not predict earthquakes – neither can we.

Categories: earthquakes, geohazards, public science, ranting, society, teaching
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Comments (4)

  1. Lab Lemming says:

    I predict that this fault will rupture within weeks of me injecting high pressure fracking waste into it…

  2. One of the most overlooked issues concerning earthquake prediction vs. prevention is that even if relatively accurate (say, 70-80 per cent accuracy) earthquake prediction were possible, it would not be the ideal solution for the problem because:

    (a) many governments (surely enough the Italian government) would take this as the “magic little pill” that makes all the pain go away and spend no more money on rendering buildings earthquake-resistent. They would thus rather accept to bear the tremendous cost of reconstruction, besides the huge social, cultural and psychological damage that would come with it.

    (b) you may tell a couple of million people in a major city for which such an earthquake prediction is made to evacuate, stay some time with countless other evacuees in schools or gymnasiums, and forego all the amenities of everyday life such as sitting in front of your TV, go to the nearby pub, meet friends and neighbors, have your kids at school, go to the church and all that. Not even in relatively poor places such as Indonesia are evacuation orders always heeded (see the disaster at Merapi volcano in 2010) – now let’s imagine in an area with relatively high living standards people are told they will be brought away from their homes and are allowed to take only the most essential things with them. Which means, leave all their material values (including a lot of fancy hi-tech stuff like HD television maxi screens) in their possibly doomed homes. And then, if the predicted earthquake does NOT occur within the predicted time window? This would be a deadly blow to the credibility of scientists (and authorities following the scientists’ advice), and someone would also have to declare that the danger is over and people may return home. Who would really, really want to be that person to make that decision, if the earthquake might in reality still occur?

    I believe that placing all our bets on earthquake prediction exclusively would create more problems than not being able of predicting earthquakes at all. Reasonably accurate earthquake prediction would only be useful in a setting where buildings are safe and all that is needed is to tell people that there is a high risk of an earthquake, so they should stay away from buildings with glass facades or other places where stuff might be falling down, and be ready to drop, cover, and hold.

  3. Lab Lemming says:

    We already have incoming surface wave earthquake warning- I heard and felt it in action last time I was in Japan. Everyone’s phone beeped an SMS, they guys checked them, said “earth quake coming, but small”, and 20 seconds later we felt the gentle swaying. Unless you happen to live right over the epicenter, those systems work well, and only fail when the threat is bigger that what civilization is engineered to withstand (e.g. Tohoku). That sort of system is more useful than 24 hour notice at 5% precision anyway, for exactly the reasons stated above.