Another earthquake, but not more earthquakes

Maggie Koerth-Baker at 9:28 AM March 11, 2010

Haiti, Chile, Turkey, Chile (again). There've been a lot of earthquakes lately. But scientists say there haven't been more earthquakes lately. Tremors are, and have always been, common. On average, per year, you can expect one 8.0 or above quake, 17 quakes between 7 and 7.9, and 130-odd quakes between 6.0 and 6.9. One thing that has risen: Death tolls. But scientists say that increase has more to do with economic conditions that drive people to pack into mega-cities and live in cheaply built (and quick-to-collapse) homes.

10 Comments Add a comment

Anon #1 10:00 on Thu, Mar.11 Reply

Also a 6.4 Earthquake in Taiwan on March 4th.

Alan #2 10:23 on Thu, Mar.11 Reply

There's a ton of factors, and it depends on who says what. On the radio on different days, I've heard that the earthquakes are hitting populated areas instead of remote nowheres like the Arctic tundra, that statistically, you'd expect some years to have more strong earthquakes than others, and of course the above statement.

BTW, the second quake in Chile is technically an aftershock of the first one, albeit one hell of an aftershock, that will lead to its own series of aftershocks. It's expected that if you have an earthquake in the 8 range that there will an aftershock in the 7 range. Notice, too, that Haiti's 7.2 had 5.9 aftershock eight days later.

Anon #3 10:32 on Thu, Mar.11 Reply
merreborn #4 12:17 on Thu, Mar.11 Reply

http://en.wikipedia.org/wiki/Availability_heuristic

It's not that there are more earthquakes this year, it's that most quakes usually don't get much media attention.

Hal #5 14:05 on Thu, Mar.11 Reply

maybe quit building major cities on fault lines?

rationalist #6 14:55 on Thu, Mar.11 Reply

Facts FTW.

PaulR #7 15:21 on Thu, Mar.11 Reply

All that, and the fact that there are more people to kill and maim, and to notice.

If an earthquake happened in the middle of the Sahara, well, they wouldn't fly in scads of reporters to take pictures of the dunes not there any more...

Cicada replied to comment from Hal #8 21:08 on Thu, Mar.11 Reply

Not a bad idea, but evacuating the Pacific Rim's gonna be kind of costly.

Anon #9 06:02 on Sun, Mar.14 Reply

Indonesia just got a few quakes. Tell them its just selection bias

Anon #10 14:54 on Sun, Apr.25 Reply

Actually, there has been an increase in major seismic activity from 1973 to 2009 (the years for which there is online information at USGS.gov)

I was curious, so I took only those quakes of 7.0 magnitude or greater for each year and compared the seismic action on a linear scale (rather than the logarithmic Richter scale). Obviously, there are years of high seismic activity and years of low activity; but, when I ran an OLS regression the slope was +0.97 per year over 37 years. This is the equivalent of one additional magnitude 7.0 earthquake EACH YEAR! Keeping in mind that the quake that recently leveled Haiti was a 7.0 magnitude quake, there are 37 more 7.0 earthquakes per year in 2009 than there were in 1973. That's significantly more shaking now than in 1973.

Anyone can do the same analysis that I did and get the same result.

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