Guest post by David Middleton
Wow! I woke up Friday morning to news that a 2.0 Md earthquake struck about a mile and a half from my office. I was sleeping at home, about 7 miles from the epicenter, and it didn’t even wake me up. Thirty years as an exploration geophysicist, and I sleep right through my first earthquake!
That morning, I arrived at work and found my office in total disarray – So the quake didn’t do any damage…
Now… I have yet to hear any journalists, politicians or college professors link this quake to fracking… But I figure they will. So I’ll just preemptively shoot that bit of junk science down. Fracking can trigger extremely minor earthquakes. A 2.0 Md quake is in the realm of possibilities. However, there aren’t any active wells within a 5 km radius (Davis et al., 1995) of this particular quake.
Now that I’ve preemptively debunked that bit of junk science, let’s go to Ohio. Every morning I like to check the Real Clear Energy website. It’s a nice compendium of energy news and also includes a fair bit of AGW nonsense. So it’s often a good source for blogging material. Well, this bit of nonsense caught my eye…
So, I clicked the link to the Scientific American article and this is what I saw…
At least they had the scientific integrity to mention that the quake was likely triggered by the wastewater injection well and not actually triggered by the fracking.
The Oklahoma Geological Survey recently examined (Holland, 2011) the possible relationship between a swarm of micro-quakes and a fracking operation in Garvin County OK. They concluded that the fracking could have triggered the 1.0 to 2.8 Md temblors. However, the quakes were so insignificant that it was almost impossible to precisely locate the hypocenters. The quakes could have been within 5 km of a fracking operation, they could have been small enough to have been triggered by the fracking operation and they occurred right after one fracking operation. However, the area has frequent seismicity of similar magnitude and no other fracking operations in the field’s 60+ year history have been correlated with induced seismicity.
After a bit of modeling, Holland was able to place the hypocenters of the temblors along a fault, within 5 km of an active fracking operation.
Holland’s conclusion was that there was a 50-50 chance that these micro-quakes were triggered by the fracking operation in the Picket Unit B Well 4-18.
One person reported feeling these quakes. Md 1.0 to 2.8 quakes are Category I on the Modified Mercalli Intensity Scale…
You have to get up to more than Md 3.5 before quakes deliver “vibrations similar to the passing of a truck.” The non-palpable seismicity that might result from fracking is less than that of a seismic crew shooting a survey. Fracking can’t cause larger quakes…
Oklahoma Earthquakes Stronger Than Fracking Tremors, Experts Say
By SETH BORENSTEIN and JONATHAN FAHEY 11/ 7/11
WASHINGTON — Thousands of times every day, drilling deep underground causes the earth to tremble. But don’t blame the surprise flurry of earthquakes in Oklahoma on man’s thirst for oil and gas, experts say.
The weekend quakes were far stronger than the puny tremors from drilling – especially the controversial practice of hydraulic fracturing.
The magnitude-5.6 quake that rocked Oklahoma three miles underground had the power of 3,800 tons of TNT, which is nearly 2,000 times stronger than the 1995 Oklahoma City bombing.
The typical energy released in tremors triggered by fracking, “is the equivalent to a gallon of milk falling off the kitchen counter,” said Stanford University geophysicist Mark Zoback.
In Oklahoma, home to 185,000 drilling wells and hundreds of injection wells, the question of man-made seismic activity comes up quickly. But so far, federal, state and academic experts say readings show that the Oklahoma quakes were natural, following the lines of a long-known fault.
“There’s a fault there,” said U.S. Geological Survey seismologist Paul Earle. “You can have an earthquake that size anywhere east of the Rockies. You don’t need a huge fault to produce an earthquake that big. It’s uncommon, but not unexpected.”
In the past, earthquakes have been linked to energy exploration and production, including from injections of enormous amounts of drilling wastewater or injections of water for geothermal power, experts said. They point to recent earthquakes in the magnitude 3 and 4 range – not big enough to cause much damage, but big enough to be felt – in Arkansas, Texas, California, England, Germany and Switzerland. And back in the 1960s, two Denver quakes in the 5.0 range were traced to deep injection of wastewater.
Holland, who has documented some of the biggest shaking associated with fracking, compared a man-made earthquake to a mosquito bite. “It’s really quite inconsequential,” he said.
Hydraulic fracturing has been practiced for decades but it has grown rapidly in recent years as drillers have learned to combine it with horizontal drilling to tap enormous reserves of natural gas and oil in the United States.
About 5 million gallons of fluid is used to fracture a typical well. That’s typically not nearly enough weight and pressure to cause more than a tiny tremor.
Earlier this year, Holland wrote a report about a different flurry of Oklahoma quakes last January – the strongest a 2.8 magnitude – that seemed to occur with hydraulic fracturing. Holland said it was a 50-50 chance that the gas drilling technique caused the tremors
So… Fracking can’t cause significant earthquakes and Seth Borenstein can actually write an article without parroting the alarmists.
References and Further Reading
Davis, S.D., P.A. Nyffenegger & C. Frolich. The 9 April 1993 Earthquake in South-Central Texas: Was It Induced by Fluid Withdrawal? Bulletin of the Seismological Society of America. Vol. 85, No, 6. pp. 1888-1895, December 1995.
Frolich, C. & E. Potter. Dallas-Forth Worth earthquakes coincident with activity associated with natural gas production. The Leading Edge. Vol. 29, No. 3. pp. 270-275, March 2010.
Holland, A. Examination of Possibly Induced Seismicity from Hydraulic Fracturing in the Eola Field, Garvin County, Oklahoma. Oklahoma Geological Survey Open-File Report OF1-2011. August 2011.