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http://news.nationalgeographic.com/news/2011/08/110824-earthquakes-today-washington-dc-richmond-virginia-science/

Is it just me or does it seem as if there has been an increase in global siesmic activity lately???

Bryant, you know anything about an increase or am I imagining things???

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it's 2012 bro!

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Originally Posted by Dødherre Mørktre:
it's 2012 bro!

Nah, this is just teh rehearsal.  

Saw a great tweet about that actually after the earthquake....

"Not to panic anyone in NYC< but a screaming John Cusack just drove by in a limo that was missing a door"

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To the best of my knowledge there isn't a significant increasing trend in the number of earthquakes.  The below chart is from the USGS and depicts the magnitude of earthquakes measured through a period of time.  Things look fairly stable.  I tried to create a similar graph of all recorded earthquakes since 1980, but Excel won't allow that many points on a graph!

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BTW, that y-axis scale of that graph is in Moment Magnitude, not Richter.  Geologists quit using Richter almost a century ago.  When you hear the anchor lady report that the East Coast quake was measured as a 5.8 on the Richter Scale she is wrong, the geologist (or geophysicist, or seismologist, whatever) she got the number from was talking moment magnitude and she didn't realize it.

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Originally Posted by Bryant Platt:
BTW, that y-axis scale of that graph is in Moment Magnitude, not Richter.  Geologists quit using Richter almost a century ago.  When you hear the anchor lady report that the East Coast quake was measured as a 5.8 on the Richter Scale she is wrong, the geologist (or geophysicist, or seismologist, whatever) she got the number from was talking moment magnitude and she didn't realize it.

I did not know that.

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Originally Posted by Bryant Platt:
To the best of my knowledge there isn't a significant increasing trend in the number of earthquakes.  The below chart is from the USGS and depicts the magnitude of earthquakes measured through a period of time.  Things look fairly stable.  I tried to create a similar graph of all recorded earthquakes since 1980, but Excel won't allow that many points on a graph!

What is the scale to use for the depths??? I'm guessing it is metric, but that would be too shallow for an origin wouldn't it???

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Originally Posted by Mark Simmons:

Originally Posted by Bryant Platt:
To the best of my knowledge there isn't a significant increasing trend in the number of earthquakes.  The below chart is from the USGS and depicts the magnitude of earthquakes measured through a period of time.  Things look fairly stable.  I tried to create a similar graph of all recorded earthquakes since 1980, but Excel won't allow that many points on a graph!

What is the scale to use for the depths??? I'm guessing it is metric, but that would be too shallow for an origin wouldn't it???

They should have specified.  I presume the scale is in Km.

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think there's any increase in the number of shallow quakes? i'm particularly curious why this pacific re-alignment seems to have triggered such a large number of more devastating quakes. chile, new zealand, japan, and now it seems probably that there's going to be a northeastern pacific shift as well. is it that this has been such a large shift?


anyway, this ought to prove entertaining due to the crazy website i found it on, but have any of you heard of this?


A grim top-secret report prepared by Moscow’s Institute of Physics of the Earth for Prime Minister Putin on the catastrophic 9.0 magnitude Sendai Megaquake and Tsunami that hit Japan on March 11th is now warning that the “balance of our planet” has been altered after the titanic forces underlying this disaster has moved the Japanese Islands at least 13-feet closer to the North American West Coast Region and shortened the day by a couple of millionths of a second and tilted the Earth’s axis slightly.

According to this report, the Sendai Megaquake disaster is the “third part” of a major “four part” realignment of the entire “Ring of Fire” Pacific Plate that began with the 8.8 magnitude Megaquake that hit Chile on February 27, 2010, continued on with the 6.3 magnitude quake that destroyed New Zealand’s second most populous city Christchurch on February 22, 2011, and this past week caused the 9.0 magnitude Megaquake that has left Japan reeling.

At 103 million square kilometers (64 million square miles), this report continues, the Pacific Plate is our World’s largest tectonic plate and the forces now being exerted by it on the Juan de Fuca Plate (located to the west of the North American Plate) due to the previous three disaster of Chile, New Zealand and Japan has brought what is called the Cascadia Subduction Zone to near “total failure” threatening the coastlines of Alaska, Western Canada and the Northwest region of the United States with catastrophic Megaquakes and tsunamis.


apparently, this came from the "european union times" paper.

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Originally Posted by Dødherre Mørktre:


apparently, this came from the "european union times" paper.

Hmm, given that 2 of the other headlines on their page are "Russia Reports Nuclear Explosions Hit Vast US Military Tunnel Network" and "Vatican set to hold conference on the Existence of Aliens", I think I'll take this one with a pinch of salt....

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Originally Posted by Dødherre Mørktre:
i'm particularly curious why this pacific re-alignment seems to have triggered such a large number of more devastating quakes. chile, new zealand, japan, and now it seems probably that there's going to be a northeastern pacific shift as well. is it that this has been such a large shift?

What do they mean re-alignment?  Its a dynamic system, constantly moving and changing geometry.  I wouldn't expect an earthquake in NZ or Japan to affect the change of rupture in the Cascadia subduction zone (although the chances of a large quake in the near future there is favorable).  The reason for this gets into why earthquakes happen.  

Earthquakes occur along faults when one part of the fault sticks due to roughness in the fault walls (imagine your sliding two pieces of coarse grit sandpaper over each other, are they going to slide smoothly?  Now imagine sliding that sandpaper with 1km of rock on top of it, how do you think it'll move?  Note that you are only getting stuck on individual grains on the paper, not over 100% of the surface).  When a segment of the fault sticks and the rest of the fault keeps moving, you strain (deform) the stuck portion and accumulate lots of stress (energy).  When the stress accumulated in the stuck portion of the fault exceeds the friction from the walls the stuck part fails, a) releasing large amounts of stored energy (earthquake) and b) allowing the stuck part of the fault to spring back to about where it would have been if it hadn't stuck.  For additional (higher quality) discussion, check out this link: http://earthquake.usgs.gov/regional/nca/1906/18april/reid.php.

Because most of the fault is still moving around the stuck part thats stuck, and because when the stuck part ruptures it jumps back to where it would have otherwise been I wouldn't expect much if any impact on plate dynamics (plate movement, which would have to be accommodated by other faults).  It is possible for a fault to become so stuck or otherwise unfavorable in the current stress regime that instead of unsticking, a new fault ruptures elsewhere and replaces it.  The deformation for that should be somewhat local, not really important on a plate scale.

anyway, this ought to prove entertaining due to the crazy website i found it on, but have any of you heard of this?


A grim top-secret report prepared by Moscow’s Institute of Physics of the Earth for Prime Minister Putin on the catastrophic 9.0 magnitude Sendai Megaquake and Tsunami that hit Japan on March 11th is now warning that the “balance of our planet” has been altered after the titanic forces underlying this disaster has moved the Japanese Islands at least 13-feet closer to the North American West Coast Region and shortened the day by a couple of millionths of a second and tilted the Earth’s axis slightly.

According to this report, the Sendai Megaquake disaster is the “third part” of a major “four part” realignment of the entire “Ring of Fire” Pacific Plate that began with the 8.8 magnitude Megaquake that hit Chile on February 27, 2010, continued on with the 6.3 magnitude quake that destroyed New Zealand’s second most populous city Christchurch on February 22, 2011, and this past week caused the 9.0 magnitude Megaquake that has left Japan reeling.

At 103 million square kilometers (64 million square miles), this report continues, the Pacific Plate is our World’s largest tectonic plate and the forces now being exerted by it on the Juan de Fuca Plate (located to the west of the North American Plate) due to the previous three disaster of Chile, New Zealand and Japan has brought what is called the Cascadia Subduction Zone to near “total failure” threatening the coastlines of Alaska, Western Canada and the Northwest region of the United States with catastrophic Megaquakes and tsunamis.

apparently, this came from the "european union times" paper.

The only thing in there that made sense to me is that Japan may have moved closer to N. America (I don't know how realistic the distance is, I'll have to look it up when I'm not feeling lazy).  Plates move, that's kinda their thing.  If we could speed the clock up fast enough shipping between the US and China will be a lot cheaper due to the consumption of the Pacific Plate by Eurasia.  That said, Eurasian plate dynamics are incredibly complex.

think there's any increase in the number of shallow quakes?

I hope you don't mind me pulling this out of its original location, I wanted to address it last.

Looking at the data from the USGS graph posted above and from the brief glimpse of the 1980-2010 5.0-5.9 earthquake graph I made before Excel crashed I would say no, there doesn't appear to be a strong shallowing trend.  If there were, what would you suspect is the reason, why?

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Originally Posted by Bryant Platt:

think there's any increase in the number of shallow quakes?

I hope you don't mind me pulling this out of its original location, I wanted to address it last.

Looking at the data from the USGS graph posted above and from the brief glimpse of the 1980-2010 5.0-5.9 earthquake graph I made before Excel crashed I would say no, there doesn't appear to be a strong shallowing trend.  If there were, what would you suspect is the reason, why?

It's those crazy friggin mole men!!!!!!!!!!

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Originally Posted by Bryant Platt:
If there were, what would you suspect is the reason, why?

just wondering if there is ANY change at all going on, or does it just seem that way?