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Squink
2014-May-06, 02:34 AM
Rare Earthquake Warning Issued for Oklahoma (http://www.livescience.com/45361-oklahoma-earthquake-risk-rising.html)
Mile for mile, there are almost as many earthquakes rattling Oklahoma as California this year. This major increase in seismic shaking led to a rare earthquake warning today (May 5) from the U.S. Geological Survey and the Oklahoma Geological Survey.

In a joint statement, the agencies said the risk of a damaging earthquake one larger than magnitude 5.0 has significantly increased in central Oklahoma.
...
This is the first time the USGS has issued an earthquake warning for a state east of the Rockies
It might just be fracking skewing the numbers:
While scientists haven't ruled out natural causes for the increase, many researchers suspect the deep injection wells used for the disposal of fracking wastewater could be causing the earthquake activity.

NEOWatcher
2014-May-06, 11:51 AM
Rare Earthquake Warning Issued for Oklahoma (http://www.livescience.com/45361-oklahoma-earthquake-risk-rising.html)
It might just be fracking skewing the numbers:
It could be, but when I looked up the earthquake activity for Oklahoma (http://earthquaketrack.com/p/united-states/oklahoma/recent) I was surprised to see the number and strengths of them.
We have had quite a bit of fracking activity in Eastern Ohio and Western PA with small quakes being attributed to it. But; hardly even a blip (http://earthquaketrack.com/p/united-states/ohio/recent) compared to OK or even our own fault location just east of Cleveland.

So; skew or contribute could be, but I can see why they are concerned.

publiusr
2014-May-10, 05:29 PM
Then too, lubrication means that later quakes won't be as damaging.

Squink
2015-Feb-23, 07:22 PM
USGS: Coping with Earthquakes Induced by Fluid Injection (http://www.usgs.gov/newsroom/article.asp?ID=4132&from=rss_home#.VOt6m3ak85n) 2/19/2015
Abstract in Science (http://www.sciencemag.org/content/347/6224/830)

mapguy
2015-Feb-24, 02:31 PM
I was surprised to read in the latest National Geographic that Oklahoma is now considered the "earthquake capital" of the U.S.
NG also cited fracking as a likely contributor to the increase in frequency and magnitude.
So now Okies get to deal with earthquakes as well as tornadoes.

Buttercup
2015-Feb-24, 03:17 PM
I was surprised to read in the latest National Geographic that Oklahoma is now considered the "earthquake capital" of the U.S.
NG also cited fracking as a likely contributor to the increase in frequency and magnitude.
So now Okies get to deal with earthquakes as well as tornadoes.

My thoughts exactly :doh: :(

And east/central Texas are apparently getting quakes now. I'm unsure how frequent or strong as compared to OK.

BigDon
2015-Feb-24, 11:18 PM
Or it's merely a new rift forming. The Oklahomans might be getting a beach!

And isn't the material being pulled out being replaced simultaneously with water?

Correlation and causation are two different things. Allow me to rehash the ol' real world example:

Increases in drowning deaths always coincide with increases in the sale of ice cream. For realies.

Now one can surmise all kinds of things with this information regarding the ice cream and drowning correlation.

But it would take some people a quite a while to come up with "hot weather" causation.

We don't know right now and the public trying to out guess the experts with wild hypotheses and guesses can hurt us.

Swift
2015-Feb-25, 01:53 AM
And isn't the material being pulled out being replaced simultaneously with water?

Actually, no.

I don't know about Oklahoma, but similar things have gone on in Ohio. And it isn't the oil or gas extraction, or the drilling and fracking of those wells that cause the earthquakes. The fracking fluids that are pumped into the extraction wells has to be disposed of (it is pumped back out before they can get the oil or gas). Those fluids have to be disposed of and a common way of disposing of them is in injection wells (http://water.epa.gov/type/groundwater/uic/basicinformation.cfm).

People have noted for some time that pumping fluids into injection wells can cause earthquakes. The problem seems to be that in areas where there is a lot of this type of drilling going on, there is a lot of waste fluids being generated and so there is a lot of injection wells being pumped into; this seems to be what is causing the quakes.

To blame the public for wild hypotheses, and to compare it thinking that ice cream sales cause drownings, is not fair.

NPR story about it (http://stateimpact.npr.org/texas/tag/earthquake/)

Hydraulic fracturing, or “fracking,” (a drilling process that injects millions of gallons of water, sand and chemicals under high pressure into a well, cracking the rock and to release natural gas and oil) has only been known to rarely cause earthquakes.

But the disposal of drilling wastewater used in fracking has now been scientifically linked to earthquakes. The fluids used in fracking (and the wastewater that comes back up the well) is disposed of by injecting it into disposal wells deep underground. This is generally regarded as the safest, most cost-efficient way to get rid of it. But in some parts of the country, especially in the Barnett Shale area around Dallas-Fort Worth, it has also been causing earthquakes. And they’re growing both in number and strength.

USGS from 2012 (and probably a little dated) (http://www.doi.gov/news/doinews/Is-the-Recent-Increase-in-Felt-Earthquakes-in-the-Central-US-Natural-or-Manmade.cfm)

While it appears likely that the observed seismicity rate changes in the middle part of the United States in recent years are manmade, it remains to be determined if they are related to either changes in production methodologies or to the rate of oil and gas production.

We also find that there is no evidence to suggest that hydraulic fracturing itself is the cause of the increased rate of earthquakes. The fact that the disposal (injection) of wastewater produced while extracting resources has the potential to cause earthquakes has long been known. One of the earliest documented case histories with a scientific consensus of wastewater inducing earthquakes, is at the Rocky Mountain Arsenal well, near Denver. There, a large volume of wastewater was injected from 1962-1966, inducing a series of earthquakes (below magnitude 5).

News story from KRMG radio from a few days ago (http://www.krmg.com/news/news/local/usgs-links-oil-and-gas-injection-wells-earthquakes/nkGfs/)

On Thursday, the United States Geological Survey weighed in on the subject.

In a press release on their website, the U.S.G.S. states, "the increased seismicity is due to fluid injection associated with new technologies that enable the extraction of oil and gas from previously unproductive reservoirs."

BigDon
2015-Feb-25, 02:39 AM
I just didn't know any thing about this other than it happens, Swift. It's outside my normal areas of interest.

Ara Pacis
2015-Feb-25, 06:01 AM
Well, there may be an existing aulacogen (http://en.wikipedia.org/wiki/Aulacogen) in Oklahoma (http://en.wikipedia.org/wiki/Southern_Oklahoma_Aulacogen).

Eclogite
2015-Feb-25, 08:01 AM
Then too, lubrication means that later quakes won't be as damaging.This, for me, is the interesting point. Let's run with the consensus view that re-injection of fracking fluids is responsible, at least in some areas, for increased seismiscity. How is this occuring?

1. Lubrication of fault planes, thereby facilitating movement.
2. Initiation of fracture planes,

In the second case movement would only occur if there is a pre-existing stress to be relieved, which brings us practically back to the condition in point 1. In short, as publiusr says, there are going to be quakes here eventually - the injection fluids are minimising the impact of those quakes by allowing early stress relief. As an aside, a lot of the low angle thrusting we see in tectonically active areas is likely facilitated by naturally occurring overpressures in pore fluids.

Squink
2015-Feb-25, 03:29 PM
1. In short, as publiusr says, there are going to be quakes here eventually - the injection fluids are minimising the impact of those quakes by allowing early stress relief.Not every stress results in strain. I've drinking glasses in my house that have stood up to internal stresses for 3 decades wo shattering. The same likely goes for internal stresses within geological strata. Without stimulation, some of those stresses will never be relieved.

Eclogite
2015-Feb-25, 09:00 PM
Not every stress results in strain. I've drinking glasses in my house that have stood up to internal stresses for 3 decades wo shattering. The same likely goes for internal stresses within geological strata. Without stimulation, some of those stresses will never be relieved.The glasses in your house have not been subject, as most rocks are, to progressively increasing stress in response to plate movement. That said some stresses may remain unrelieved, but I suspect the majority will build until movement occurs. (Please note my use of the word suspect. If I can find research to support this contention I shall post it - if not it remains a simple opinion.) And I am ignoring, properly I think, the many stresses, such as simple overburden load, that 'require' no relief.