16

First it was New Zealand, now Japan -- two major earthquakes in a span of less than 2 months. Cults could use this opportunity to sell their end-day stories.

Joking aside, is there any scientific evidence showing that seismic activity has become more and more frequent these days?

  • 2
    What time span are you talking about? The last 4 months, the last 4000 years? 4 million years? These days sounds like something in a human time span - maybe 100 years? – user unknown May 28 '11 at 22:50
  • I will admit that I would be curious as to whether this situation has changed in recent years. I've seen multiple claims that fracking is causing more earthquakes... – Sean Duggan Apr 22 '16 at 14:38
19

Actually not. It happened that those two earthquakes get media attention because they happen in developed countries.

Actually there are earthquakes daily around the Earth. A vast majority of them is not harmful because the magnitude is low, or also because the epicentre lies from inhabited places.

Read about Clustering illusion to know what can produce the feeling you describe.

  • I remember an earthquake in Haiti, one of the poorest countries of our planet, which got a lot of attention too. – user unknown May 30 '11 at 0:00
  • @user unknown: In the case of Haiti it got attention because it was a really huge earthquake in a heavily populated area. Also Haiti is located close to very developed countries. – Benoit Jun 4 '11 at 9:02
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    The earthquake in New Zealand and Japan happened in heavily populated areas too. So I guesss that is the major reason for mass media interest, not the development of the countries. Changing the reason for every second incident doesn't look very seriously. – user unknown Jun 4 '11 at 12:44
9

Here is a list of the 10 largest earthquakes measured since 1900. We have about 1.3 Million earthquakes of magnitude 2 to 2.9, and 134 of 6 to 6.9 per year. But most of them happen in the sea, in deserts or far from cities.

But we have an increasing world population, so the number of affected persons can climb over the century. We have increasing numbers of artifacts which can be damaged, and therefore increasing damages in form of costs, while predictions of earthquakes get better, and the number of EQ-resistant builduings increases, which meanwhile lowers, but doesn't compensate, the damages.

And we have an increasing number of stations which measure EQs.

Numbers of USGS and GFZ Potsdam

Oh - I forgot the answer: :)

NO

For the last 100 years, there is no increasing number of EQs. But the timespan of interest might be choosen to fit the claim. You could watch just for a few weeks and EQs stronger than x.

I guess it isn't possible to count prehistoric earthquakes today.

0

This kind of conclusion suffer from the problem of lack of baseline level. How many major earthquake per year should be considered normal? Almost nobody have the slightest idea. This does stop people from saying that some catastrophic event is happening more frequently than it should. Without the baseline, the reasoning is clearly invalid. The issue is that this is a rare event. So when it does strike, people subjectively see it happen more than it "should". Also people will almost never arrive in the opposite conclusion. E.g. "we are without a significant earthquake in the last 100 years, this is not normal..." No, this doesn't bother them because earthquake is suppose to be rare.

The covers the reasoning of general public. I have no information on any comprehensive scientific study on the earthquake frequency. One thing is certain, you need far more data than just 2 major earthquake to draw any valid conclusion.

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