Good Science And Bad

Two of the organisers of TEDx have published a letter to the TEDx community encouraging people to think before putting someone on stage. They note that there is no single test to establish whether what someone is promoting is good or bad science, but there are a lot of inidcations one can use, both positive and negative.

I think it is pretty good, and I’d encourage people to use it when trying to work out for themselves whether something they have found online is accurate. However, there is one thing I would add: If you like the conclusion of a piece, probe it more, not less.

It’s not an easy habit to get into, and I can’t say I am great at it, but like most things one gets better with practise. It is very, very rare that a single scientific study settles a question one way or another. So if you see something you might want to use as evidence for your case, try to think about how reliable the research may be. The suggestions Lara Stein and Emily McManus give are good places to start. Those who are opposed to GMOs or think their could be a dietary basis for autism would be well advised to take on board the negative references to practitioners of both fields. There are plenty of good reasons to be worried about GMOs, for example, but that doesn’t erase the fact that there are lots of cranks opposing them for reasons that require us to throw out everything we’ve learnt about biology in the last 50 years. I don’t know whether there is any basis for linking autism to diet, but even if there is, it doesn’t justify the nutjobs who propose connections based on easily refuted evidence.

Writing for Australasian Science I seldom have the time or space to consult other experts in the field to get alternative views on new research. I try to flag to my readership that the studies I am writing about should not be taken at face value through the verbs I use. I prefer “XY university scientists have claimed” to “”XY scientists have discovered” for example. The more uncertain the research seems to me, the more I try to throw in these sorts of clues. Occasional however, I do work where I don’t feel the need to do this, and this week saw one example. I think the research is pretty interesting in itself, but I’m going to write about it here so I can explain why I think it is more unusually likely to be solid.

Dieter Muller of the University of Sydney has produced evidence that the largest earthquakes occur where subduction zones and fracture zones meet. This could help us reduce the damage from future earthquakes, and particularly tsunamis, potentially saving tens of thousands of lives.

Confused? Subduction zones, far from places where geologists get laid, are places where one tectonic plate is slowly slipping under another. Examples include the India Plate sliding under the Burma Plate and the Pacific Ocean Plate being overridden by almost everybody. It is known that subduction zones are the sites of the world’s larges earthquakes, and since they usually lie underwater, the main trigger for tsunamis. However, there are many, many kilometres of subduction zones in the world, and only some have been the locations for large earthquakes since we have had seismometers. This raises questions: Are all subduction zones dangerous? Do we need to be worrying about tsunamis from all the Earth’s subduction zones, or only a few? If there has not been an earthquake somewhere for a while does that mean that the areas is safe, of that the forces are simply building up for release in a really, really big one?

Two subduction zones that were thought probably safe were in the Indian Ocean off Sumatra and where the Pacific plate is subducting under northern Honshu. 2004 and 2011 proved those wrong, at the cost of many, many lives. Even if we had known about the risk of an Indian Ocean tsunami we could probably not have prevented most of the destruction for a price the world would have been willing to pay. But cheap preparations might have saved 10% of the lives, which would still have been a very good thing. If Japan had recognised the danger it faced Fukashima might be a name known merely as the site of a really high sea wall.

After the Tohoku earthquake and tsunami Muller expected to be called by the media, so he took a look at the geology of the location. “The first thing I noticed,” he told me “Is that there is a huge ridge from a fracture zone meeting the subduction zone right there.” I’m having trouble finding a way to explain fracture zones, so I will outsource this to wikipedia. However, perhaps the key point is that, despite their scary name, fracture zones have been considered geologically stable.

Most of the time they are, but Muller started looking and noticed that, in combination with subduction zones they produce the biggest earth quakes. By random chance one would expect a quarter of the earthquakes in subduction zones to occur near fracture zones, and Muller found that for small and medium sized quakes this is indeed the case. But half the quakes above 8.4 on record have occurred at these locations, and 13 of the top 15. It’s these big ones that really do the damage and we need to be ready for.

Muller doesn’t have a definitive explanation for this link, but suspects that the ridges that are a feature of fracture zones have trouble slipping under the overriding plate. “There is more friction and tension builds up, to be released in one large earthquake rather than many small ones.”

While we can’t entirely relax about subduction zones without fractures (there are still 2 of the top 15 to account for) this suggests our main focus should be on places where fracture zones cross. If we’d noticed this trend before 2004 (when it was just 11 out of 13) we would have been a lot more ready for both the Indonesian and Tohoku disasters. Muller identifies the Pacific ocean off the Canadian/American border as the place that hasn’t had a large quake we know of, but may just be building up pressure for something really bad. It’s wonderful to hear that the first call he got after publishing the paper was from British Columbia disaster planners. I hope Seattle is on to it too, although the shape of the sound may provide protection.

Why do I find this work so much more convincing than most. After all, a sample of 15 is not something I would usually accept. Mainly because it is so easily checkable. Muller provides a map of the relevant areas, including locations for the top 15 and top 50 quakes. You can see the pattern with the naked eye. I’m sure this work has sent a tremor (pun intended) though the seismological community. If any of the quake locations are wrong someone would be onto it in less time than it takes for a tsunami to cross a narrow strait. His explanation makes sense, but may be proven wrong, but the correlation is almost certainly solid.


About Stephen Luntz

I am a science journalist, specialising in Australian and New Zealand research across all fields of science. My book, Forensics, Fossils and Fruitbats: A Field Guide to Australian Scientists is out now through CSIRO Publishing. I am also a professional returning officer for non-government organisations. I'm very politically active, but generally try to restrict this blog to scientific matters.
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