The controversial process used to extract natural gas from deep underground rock formations has come under even more scrutiny after Youngstown, Ohio was shaken Saturday by a 4.0 magnitude earthquake, the strongest of the 11 quakes recorded in the Youngstown area since March.
[EDITOR'S NOTE: This blog has been altered since its initial publication to correct the causes of the Ohio earthquakes. The injection of fracking wastewater deep underground, not the fracking process itself, is blamed for the Youngstown, Ohio earthquakes. The Ind regrets the error.]
First it was air pollution. Then it was groundwater contamination. Now, fracking - the controversial process used to extract natural gas from thousands of feet below the earth's surface - has been linked to a series of rare earthquakes in Ohio and other states, the most recent of which occurred in Youngstown, Ohio Saturday and has halted drilling at certain Ohio fracking sites until further notice.
Hydraulic fracturing, or fracking, taps into pockets of natural gas stored in shale formations deep underground (sometimes depths of more than 10,000 feet below the surface) by shooting chemicals and other liquid to fracture rock formations and subsequently release trapped natural gas.
The wastewater from fracking is then injected back into the earth, where in Ohio it apparently has migrated along fault lines and caused almost a dozen earthquakes in the Youngstown area.
"Fracking" in north Louisiana's Haynesville Shale has carried natural gas production levels in Louisiana to their highest in more than 25 years, but several recent reports question whether oil and gas industry leaders are accurate in their assertions that the process is a safe one.
According to a New York Times report, Youngstown was hit with a 2.7-magnitude tremor on Christmas Eve, its 10th since March. The origin of the earthquake, the NYT reports, was 2,000 feet below an injection well used for fracking. The next day, an even stronger 4.0-magnitude quake struck the town again:
With the increased production of gas from shale in the United States, the process of hydraulic fracturing, or fracking, has come under fire for its potential to pollute the air and contaminate drinking water. But the events in Youngstown - and a string of mostly small tremors in Arkansas, Oklahoma, Texas, British Columbia and other shale-gas-producing areas - suggest that the technique may lead, directly or indirectly, to a dangerous earthquake.
The state asked on Friday that injection at the well be halted after analysis of the 10th earthquake, a 2.7-magnitude temblor on Dec. 24, showed that it occurred less than 2,000 feet below the well. Because of a lack of data, depth estimates of earlier earthquakes had been far less precise.
The owner of the well, D&L Energy Group of Youngstown, stopped injection at 5 p.m. Friday.
When the stronger quake occurred less than 24 hours later, state officials decided to institute a moratorium on the injection of drilling waste within a five-mile radius of the well, "until we are able to take a closer look at the earthquake data that is available."
The vice president of Ohio's Oil and Gas Association, Thomas E. Stewart - or Don Brigg's doppelganger - rebuked any claims that tie the earthquakes to fracking, instead accusing oil and gas opponents of trying to "create hysteria."
But a Dec. 14 article from Bloomberg points out that other states have stopped certain injection wells of this type due to the dramatic increase in earthquakes occurring near the sites:
The Arkansas Oil and Gas Commission did stop well disposal in August after a swarm of earthquakes. There were about 1,250 quakes recorded through July after two injection wells started operating last year, said Scott Ausbrooks, geohazards supervisor for the Arkansas Geological Survey in Little Rock.
Ausbrooks did a study with the University of Memphis and concluded there was "a plausible relationship between the injection wells and the earthquakes" after a previously unknown fault system was discovered, he said.
After the wells were shut down, there were only four earthquakes recorded in the area from July through October, down from an average of four a day, Ausbrooks said.
The Oklahoma Geological Survey concluded in an August report that it might have induced 43 temblors near Elmore City during 24 hours in January. Cuadrilla Resources Ltd., a U.K.-based explorer, also suspended fracking near Blackpool, England, in June based on a concern it may have triggered a quake.
Read more on the recent fracking developments here and here.