Drop some geology knowledge on me!
March 12, 2011 7:18 AM   Subscribe

What is the significance of the seismic activity in recent years?

What is the significance of the seismic activity in recent years? It seems to me there have been a lot more significant seismic events as of late. Has there actually been a noticed increase in seismic activity, or is this par for our geological course? Is our planet undergoing a period geologic change, or is it always in a state of constant change?

I have a very basic understanding of tectonics (Geology 101, holla!), but I'm really interested in learning more. Links, books, documentaries and lengthy detailed comments are appreciated. There's a few good resources in this thread, but I want MOAR!
posted by bloody_bonnie to Science & Nature (11 answers total) 2 users marked this as a favorite
 
Basically, no. Or if there is some significance, we can't figure it out.
posted by gjc at 7:31 AM on March 12, 2011


No, there has not been an increase in the frequency of earthquakes.

What there has been has been an increase in globalized news, instant communications, and other technologies that make news travel around the world almost as fast as the earthquake's waves (not the tsunami waves).
posted by dfriedman at 7:31 AM on March 12, 2011 [3 favorites]


I am not convinced that there is more seismic activity. I think that were better at detecting it. Also, the las century has brought instant communication so that we are aware of what's going on around the globe more than at any time in history.
posted by brownrd at 7:32 AM on March 12, 2011


Best answer: Paul Kedrosky provides a few links to geologists discussing the earthquake here.
posted by dfriedman at 7:32 AM on March 12, 2011


My understanding is that part of this is that the population of the earth is growing, and therefore earthquakes are more likely now to occur in places with high population density, because there are more places with high population density. Add to that better communications and the fact that migration means that people in other places are more likely to have connections to any random part of the globe, and you get a recipe for hearing more about earthquakes.
posted by craichead at 7:42 AM on March 12, 2011 [1 favorite]


Best answer: I take notes for students with disabilities in a Geography class, and the prof took this question on the other day. The answer, quite simply, was that the frequency and severity of seismic events hasn't changed all that much since we started recording the information. See this graph by the USGS if you want visual confirmation of this. I assume this is because the tectonic processes involved, though not stable per se, are so slowly changing that in terms of our lifespan they might as well be seen as stable.

But he did say exactly what has been said above by other posters - that it is the information technology that makes it seem like there's more going on than there was in the past. So it just seems like there's more going on.
posted by vckeating at 7:48 AM on March 12, 2011


A couple factors are also at play:

- the world population has never been higher, so the number of earthquakes in "uninhabited wastes" is declining;
- the world population is also increasingly urban, so there are more shoddy buildings to collapse;
and
- we now have world-circling communications, and 24-hour news cycles, so we're more likely to hear about (and see!) earthquakes in distant lands.

When a million people were killed in a Chinese earthquake as recently as the '70s, here in the West we scarcely heard about it.

(or, on preview, what craichead said).
posted by AsYouKnow Bob at 7:50 AM on March 12, 2011 [1 favorite]


See "Misleading Vividness".
posted by Chocolate Pickle at 8:31 AM on March 12, 2011


When a million people were killed in a Chinese earthquake as recently as the '70s, here in the West we scarcely heard about it.

I came here to mention exactly this. The West learned almost nothing about the 1976 quake, because China was a closed society and information couldn't get out over the internet. Compare that to the huge amount of coverage given around the world to the (much less deadly, though still very deadly) 2008 quake. Generally, when the question in respect of natural phenomena is, "Why is X happening so much more these days?", the answer has more to do with our perception than with reality.
posted by Dasein at 10:33 AM on March 12, 2011


Generally, when the question in respect of natural phenomena is, "Why is X happening so much more these days?", the answer has more to do with our perception than with reality.

It's not even confined to natural phenomena; there's a widespread perception that violent crime is on the rise in the U.S., particularly crimes against children, when in fact it's been dropping for decades. What's risen is the constant (and wildly sensationalistic) reporting, first via the explosion of cable news and the development of the 24-hour news cycle, and then the development of the internet.
posted by scody at 12:46 PM on March 12, 2011


It is far easier to discover earthquakes now than it was ten or twenty years ago.

This. My childhood friend's father worked for the California Geological Survey, and even in the mid-1990s (ie, most people had the internet but it wasn't that useful yet) I remember that pretty much everyone we knew would call him when we felt something to see what was going on, reasoning that he would have been contacted and might know how big it was and where the epicenter was. Most people, I assume, did not know a geologist, and didn't have anyone to call, and maybe they'd hear about the quake in the paper the next day, or maybe they'd just forget about it. I was over at their house for a minor temblor once and remember the phone ringing off the hook for the next hour.
posted by troublesome at 8:32 PM on March 12, 2011


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