Study ties oil, gas production to Midwest quakes

Apr 07, 2012 By MALCOLM RITTER , AP Science Writer

Oil and gas production may explain a sharp increase in small earthquakes in the nation's midsection, a new study from the U.S. Geological Survey suggests.

The rate has jumped six-fold from the late 20th century through last year, the team reports, and the changes are "almost certainly man-made."

Outside experts were split in their opinions about the report, which is not yet published but is due to be presented at a meeting later this month.

The study said a relatively mild increase starting in 2001 comes from increased quake activity in a methane production area along the state line between Colorado and New Mexico. The increase began about the time that began there, so there's a "clear possibility" of a link, says lead author William Ellsworth of the USGS.

The increase over the nation's midsection has gotten steeper since 2009, due to more quakes in a variety of oil and areas, including some in Arkansas and Oklahoma, the researchers say.

It's not clear how the rates might be related to oil and gas production, the study authors said. They note that others have linked earthquakes to injecting huge amounts of leftover deep into the earth.

There has been concern about potential earthquakes from a smaller-scale injection of fluids during a process known as , or fracking, which is used to recover gas. But Ellsworth said Friday he is confident that fracking is not responsible for the earthquake trends his study found, based on prior studies.

The study covers a swath of the that lies roughly west of Ohio and east of Utah. It counted earthquakes of magnitude 3 and above.

Magnitude 3 quakes are mild, and may be felt by only a few people in the upper floors of buildings, or may cause parked cars to rock slightly. The biggest counted in the study was a magnitude-5.6 that hit Oklahoma last Nov. 5, damaging dozens of homes. Experts said it was too strong to be linked to oil and gas production.

The researchers reported that from 1970 to 2000, the region they studied averaged about 21 quakes a year. That rose to about 29 a year for 2001 through 2008, they wrote, and the three following years produced totals of 50, 87 and 134, respectively.

The study results make sense and are likely due to man-made stress in the ground, said Rowena Lohman, a Cornell University geophysicist.

"The key thing to remember is magnitude 3s are really small," Lohman said. "We've seen this sort of behavior in the western United States for a long time."

Usually, it's with geothermal energy, dams or prospecting. With magnitude 4 quakes, a person standing on top of them would at most feel like a sharp jolt, but mostly don't last long enough to be a problem for buildings, she said.

The idea is to understand how the man-made activity triggers quakes, she said. One possibility is that the injected fluids change the friction and stickiness of minerals on fault lines. Another concept is that they change the below-surface pressure because the fluid is trapped and builds, and then "sets off something that's about ready to go anyway," Lohman said.

But another expert was not convinced of a link to oil and gas operations.

Austin Holland, the Oklahoma state seismologist, said the new work presents an "interesting hypothesis" but that the increase in earthquake rates could simply be the result of natural processes.

Holland said clusters of quakes can occur naturally, and that scientists do not yet fully understand the natural cycles of seismic activity in the central United States. Comprehensive earthquake records for the region go back only a few decades, he said, while natural cycles stretch for tens of thousands of years. So too little is known to rule out natural processes for causing the increase, he said.

Explore further: Clean air: Fewer sources for self-cleaning

More information: Study abstract: http://bit.ly/HmqAxx

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User comments : 11

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Rosser
2.7 / 5 (3) Apr 07, 2012
Note that you can also tie the phases of the moon to the stock market. Point being, unless you can show causality, this isn't research, it's guessing. Among other things, it fails to explain why there is no similar increase in quake activity east of Ohio. This area includes West Virginia which has historically had, and continues to have some of the highest oil and gas drilling activity in the United States. Please get back to me when you have proof, not fear mongering.
Tennex
3 / 5 (4) Apr 07, 2012
Well, some examples already point to this connection (1, 2). If you drill the underground and make cavities in it with pumping of oil and gas from there, it CAN simply cause the disbalance and subsequent quakes - and no rocket physics is required for this understanding.

The phases of Moon can be tied to stock market in dense aether model, because the
gravitational shadow of moon is connected with increased concentration of neutrinos around the Earth, which are influencing the spreading of neural waves in brains and making the people nervous. So if you need some theory for it, here it is...
rikvanriel
3.7 / 5 (3) Apr 07, 2012
Extraction has been known to cause soil subsidence (and tiny quakes) in north-western Europe. However, this causes damage so rarely that oil and gas companies could simply get billed for any damages without it hurting their bottom line at all.

When damage happens, it is never due to any shaking (magnitude 3-4 is tiny) but when a house happens to be built across the border of an area that subsided.
Tennex
3.7 / 5 (3) Apr 07, 2012
..Extraction has been known to cause soil subsidence (and tiny quakes) in north-western Europe. However, this causes damage so rarely..
It depends where are you mining - the extraction in the tectonic zone could become a source of quakes way often, than at the nort-west Europe.
Horus
1 / 5 (1) Apr 07, 2012
Everyone raise their hand if they are a hydrologist, have a Ph.D in Geology and Geophysics. If not, stfu on speculating the credibility of this research.
Dzmonkeys
1 / 5 (2) Apr 07, 2012
If were not causing global warming; we must be cracking the earth in half by drilling...
NotParker
1 / 5 (2) Apr 08, 2012
""We've seen this sort of behavior in the western United States for a long time."

Usually, it's with geothermal energy, dams or prospecting. "
Feldagast
1 / 5 (1) Apr 08, 2012
Anyone think that this might be beneficial? By causing these minor quakes it is keeping stressed from building up. Aren't major quakes the result of prolonged building up of stresses?
Dug
1 / 5 (2) Apr 08, 2012
"so there's a "clear possibility" of a link," - Anything is "possible," but most credible scientist work with things that have significant probability? Which is something this article fails to establish.
vidyunmaya
1 / 5 (1) Apr 08, 2012
You are looking at -How many punches Humanity is giving to the Earth -Ball and sequential data. This is required- Save Earth Planet and Life Support- Wisdom must prevail upon - comprehensive approach.
please widen the horizons
Argiod
1 / 5 (2) Apr 09, 2012
Seems to me that when you take something out of the ground, you leave a hole where it was. Create a big enough hole and things are bound to sink into it; water can get into it, acting as a lubricant, causing rock interfaces to slide... Are these possibilities so simple as to be out of the question?

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