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"  Nationally renowned researchers and state officials are still investigating a series of earthquakes that rippled across normally placid eastern Ohio in recent months, trying to determine for certain whether a Class II injection well\u2014the EPA&amp;#039;s designation for wells designed to pump brackish, chemical-laced wastewater from gas-drilling operations\u2014was the cause. So far, the evidence seems to indicate that it was: that the quakes were a rare but difficult to predict and perhaps unavoidable consequence of the natural gas boom that has seized the region.  The quakes have prompted the state to impose a limited moratorium on the development of a handful of injection wells clustered around the epicenter. And while most analysts believe it is unlikely that moratorium will be expanded, the quakes have aggravated the fault lines between industry supporters and critics who contend that the industry is downplaying the risks associated, directly and indirectly, with the process of hydraulic fracturing deep into the earth. Andy Ware, deputy director of the Ohio Department of Natural Resources, which oversees oil and gas operations in the state, says that last week&amp;#039;s quakes\u2014the latest in a series that began more than seven months ago\u2014all appear to have been centered within 2 miles of an 18-month-old well. Much of the wastewater injected there came from drilling operations in Pennsylvania, where energy companies are tapping the vast formation of natural-gas-rich Marcellus Shale. Disposing of wastewater by injecting it into impermeable rock formations deep underground is standard practice in oil- and gas-drilling hotbeds such as Texas\u2014only the rock under Pennsylvania is not porous enough to contain it. Instead, the industry pays Ohio, which has the right kind of geology, to inject the wastewater that can&amp;#039;t be recycled into another well.  The Ohio quakes were comparatively minor: The largest, a magnitude-4.0 one on New Year&amp;#039;s Eve, rattled windows but caused no reports of significant damage. Yet they came on the heels of similar tremors near wastewater injection wells in Arkansas, Oklahoma, and Colorado. The drilling industry maintains that such earthquakes are rare and isolated events, and that the Environmental Protection Agency endorses injection wells. The oil and gas industry, together with agriculture, manufacturing, and chemical industries, disposes of millions of gallons of wastewater in thousands of deep-injection wells across the nation every day. But since as far back as the 1960s, scientists have also known that under certain rare circumstances disposing of wastewater in deep-injection wells can trigger earthquakes. Like a Skater on a Frozen Pond The link between drilling and earthquakes first came to light in 1963, when a series of quakes, the largest a 5.5, ripped through the earth beneath the Rocky Mountain Arsenal in Colorado. Authorities had drilled a 12,000-foot injection well there to handle waste from chemical weapons manufacture. A couple of years later, the federal government and Chevron conducted a series of controlled experiments at a depleted oil field in Rangely, Colo., which effectively demonstrated that pumping high volumes of water into previously unknown faults could induce earthquakes. Penn State professor Terry Engelder, an expert on the Marcellus Shale&amp;#039;s geology and gas reserves, tells PM how this works: The water, pumped in at thousands of pounds of pressure per square inch, lifts the stress holding two moving plates against each other and allows them to slide. Essentially, it&amp;#039;s the same process that allows an ice skater to skim across the surface of a frozen pond, he says. &amp;quot;By injecting water into areas that may have faults in a critical state of stress\u2014they&amp;#039;re just about ready to slip anyway\u2014you&amp;#039;re turning that fault zone into the blade of an ice skate.&amp;quot;  Though a final determination could be months away, researchers and investigators suspect that the same process may have played a role in the recent Youngstown quakes. The 9000-foot-deep well in question, called Northstar Number 1, was designed to handle wastewater and brine pumped in at up to 2500 pounds of pressure per square inch. The state approved it in 2010, according to Heidi Hetzel-Evans, communication&amp;#039;s manager for the Ohio Department of Natural Resources Division of Oil and Gas. Over the next 11 months, the well accepted vast amounts of wastewater\u2014more than half of it from out-of-state sources, she says.  But then, on March 17, 2011, the first of what would be 11 earthquakes rattled this normally seismically silent area. The first quakes were small, researchers say, registering about 2.0 and barely severe enough to be felt without the aid of sensitive monitoring equipment. The quakes were persistent, though, and by the end of the year state officials asked experts from Columbia University&amp;#039;s Lamont Doherty Earth Observatory in New York to begin monitoring seismic activities at the well. Researchers from Lamont set up four monitoring stations on Dec. 1, and they were in place to record a magnitude 2.7 quake that shook the region on Christmas Eve. A week later, at 3:05 pm on Dec. 31, the 4.0 earthquake rumbled across the region. After consulting with the Department of Natural Resources, owner D&amp;amp;amp;L Energy voluntarily shut down the Ohio well, according to Vince Bevaqua of Shale Comm, a public relations firm retained by D&amp;amp;amp;L. Meanwhile, the state imposed an indefinite moratorium on further development of four other disposal wells under construction in the area. This month the company has brought in an array of water tanks to catch flowback water as the company works to reduce water pressure into the well. By this past Thursday, pressure inside the well had dropped to about 1300 psi, Bevaqua says, about half the normal pressure. Once the pressure is relieved, he says, the company plans to bring in independent analysts to determine whether the operations at the Northstar Number 1 well caused the quakes, or whether it and the other wells in area can resume work. Although these Ohio wells take most of the wastewater exported by fracking operations in Pennsylvania, Travis Windle, a spokesman for the Marcellus Shale Coalition, an industry group representing drillers, says that shutting down the Northstar well &amp;quot;has had virtually no impact&amp;quot; on the flow of wastewater from active gas fields of Pennsylvania. &amp;quot;That&amp;#039;s because there&amp;#039;s been a sea change in water management in the Marcellus,&amp;quot; Windle says. &amp;quot;We&amp;#039;re recycling more, and disposing less.&amp;quot; The industry estimates that is now recycles 90 percent of the water it uses to frack wells. Yet the Marcellus still generates enough waste, an estimated 1.03 million gallons a day, to require 177 deep-injection wells in Ohio. Unpredictable? Those Ohio wells, which represent less than 1 percent of all the Class II injection wells in the nation, are generally considered safe. And they should be, says Won-Young Kim, a professor of seismology at Lamont-Doherty, who has been analyzing the results from the Northstar well. Despite isolated incidents in which deep-well injection has been linked to seismic activity, he says, the process remains the EPA&amp;#039;s preferred method of disposing of wastewater because it reduces the risk of surface spills or other mishaps. In the vast majority of cases, Kim says, the operations work as intended: The highly pressurized water, blasted as deep as 2 miles into porous sandstone or similar rock, slowly and predictably spreads out, losing pressure as it goes. &amp;quot;It slips through the rock and stays there forever,&amp;quot; he says. Tremors caused by wastewater injection are rare, Kim says. &amp;quot;Not every injection well triggers an earthquake. In this case, you have 177 injection wells in Ohio regionally, but only one or two got in trouble,&amp;quot; he says. &amp;quot;Obviously there&amp;#039;s a one percent chance [of an injection well causing seismic activity]. It looks like if there are no weak zones in the basement rocks they are injecting into, it will probably be okay.&amp;quot; The problem arises when the water is pumped into a basement rock strata already comprising previously undetected faults, he says. That is precisely what happened a decade ago and 50 miles away in Ashtabula, Ohio. A series of quakes emanating from a deep-well-injection facility over a period of years shook the northeastern corner of the state, culminating in a magnitude 4.5 quake in January 2001. That quake occurred almost two years after the well had stopped operating. And it&amp;#039;s what investigators believe is likely to have happened in Youngstown last week.  But can we find these faults and weak spots in layers of rock 2 miles deep before drilling deep-injection wells?  &amp;quot;We can,&amp;quot; Kim says. &amp;quot;But I think that would be a very expensive geological survey,&amp;quot; requiring costly and complicated seismic testing. And, Engelder says, even in the unlikely event that such extensive analyses were to be undertaken, there would be no guarantees of success. &amp;quot;What we&amp;#039;re talking about are the limitations of earthquake prediction,&amp;quot; Engelder says. It&amp;#039;s an imperfect science at best. Consider cases like the 1994 Northridge earthquake that sent a magnitude 6.7 quake ripping through southern California: It happened along a previously undiscovered fault line. &amp;quot;That was a big one,&amp;quot; Engelder says. Detecting minor faults like those in Ohio could prove virtually impossible. &amp;quot;Here, faults ... may be small enough that they would be impossible to detect seismically,&amp;quot; Engelder says. &amp;quot;And so I don&amp;#039;t think it can be done, largely because the scale of seismic resolution may not allow the detection of these things. The fact is, we&amp;#039;re demonstrating that the best way to find them is to drill a disposal well and pump water down there.&amp;quot; That may not be a satisfactory answer for Ohio homeowners\u2014or for homeowners in Pennsylvania, many of who are already wary of the water going down, and coming back up, wells sunk into the Marcellus Shale. But geologically, an earthquake now and then may be an unavoidable consequence of the enthusiastic pursuit of natural gas. Seamus McGraw is the author of The End of Country, a book about the Marcellus Shale. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/science/environment/a7384/are-fracking-wastewater-wells-causing-ohios-earthquakes/>