Does hydraulic fracturing, and use of deep injection wells for disposal of drilling waste fluids, cause earthquakes? That is a question being asked of industry, scientists and government leaders on a regular basis these days. The answer is alarming, yet most often denied or overlooked by people in the oil and gas industry and the local, state and federal government regulators who oversee their operations. But, the facts are not lost on geologists and geophysical engineering scientists who study these matters.
Reading from a report by the US Geological Survey (USGS), "Within the United States, injection of fluid into deep wells has triggered documented earthquakes in Colorado, Texas, New York, New Mexico, Nebraska, and Ohio and possibly in Oklahoma, Louisiana, and Mississippi. Investigations of these cases have led to some understanding of the probable physical mechanism of the triggering and of the criteria for predicting whether future earthquakes will be triggered, based on the local state of stress in the Earth's crust, the injection pressure, and the physical and the hydrological properties of the rocks into which the fluid is being injected."
At least as far back as the 1960's, the use of injected fluids to cause minor earthquakes has been used to relieve stress along tectonic fault lines. By allowing minor shifts of the plates along a fault line much larger earthquakes are mitigated or prevented. The process works by lubrication and liquification of the rock and soil holding plates in place against one another due to friction. By reducing or eliminating that friction plates are allowed to slide against one another producing earthquakes. We generally take it for granted that the earth is solid and that the ground does not move, but in reality the earth is badly fractured naturally, and already tends to move on occasion.
Everywhere you find a mountain range you will also find multiple major fault lines that produce those mountains. The San Andreas Fault that runs generally north to south through most of California is the best known example of a naturally-occurring fault line, and its history for producing major earthquakes is well known and documented. As the magma of the earth's core is hearted and pushed upward with great force it displaces the rock and soil in the mantle of the earth above it resulting in volcanoes and earthquakes. Tall mountains are indicators of immensely powerful displacement forces at work moving the earth to form those magnificent ranges that cause humans to wonder in awe at their formation.
Liquification refers to turning dry sand and soil into a slimy mud that reduces friction between geologic plates. Lubrication refers to "oiling" the surface of geologic plates so that friction between masses of rock is reduced. In combination with the upward pressure being exerted by the core of the earth plates tend to slide against one another with one plate sliding under the other causing it to rise above the surface. The result of such activity is hills, mountains and valleys. But, how much force does it take to move the earth? Considering the trillions of tons of weight the surface of the eart exerts on its core, the energy needed to displace all that rock and soil is tremendous - more than the power of all the bombs that have ever been exploded on the earth combined - by many thousands or millions of times over.
While there are definitely tectonic plates running through Texas, earthquakes are not something that Texans experience on a regular basis. In fact, most Texans have never felt an earthquake on Texas soil even it they have lived here for decades, or longer. That is not to say that earthquakes do not occur - they certainly do, but most are not strong enough to be felt. The USGS measures all detectable quakes and records all available data about them, so the record is there to substantiate that earthquakes do occur in Texas, which brings us to the subject of earthquakes caused by hydraulic fracturing and deep well injection for disposal of drilling wastewater.
Can it be definitively stated that hydraulic fracturing causes earthquakes? Yes! It does not happen often, but it has and does happen occasionally. That is a scientifically documented fact. But, the reality is that many earthquakes are at least the indirect result of frac'ing because if wells were not being frac'ed, then all that wastewater would not have to be disposed of in deep injection wells. So, even if the act of frac'ing itself is not the major cause of earthquakes it is certainly the major contributing factor since it creates the necessity of the very activity that is most directly related to man-made earthquakes - hydraulic fracturing and the contaminated wastewater it produces.
Cliff Frohlich, the senior research scientist at the University of Texas' Institute for Geophysics, has stated, "There are different levels of good news. Even if things do turn out to be more serious than we thought, they do have options. But however one views it, industry and government officials need to take the issue of man-made earthquakes seriously as drilling spreads across the country to more densely populated areas. There are organizations that would like to ignore this. My study suggests you can't ignore it. I don't see a major problem. But it does need to be addressed." Frohlich's peer-reviewed study can be found at http://www.eenews.net/assets/2012/08/06/document_pm_01.pdf.
Doubters often cite the difference between the depth of wells and the depth of earthquakes as "evidence" that no cause and effect relationship exists. A recent comment board statement claimed that an earthquake near DFW International Airport on the morning of January 22, 2013 could not have been caused by a deep injection disposal well operation because the earthquake was centered ten miles (52,800 feet) beneath the surface and injection wells only go "a few thousand feet deep" - typical Barnett Shale injection wells are sunk 15-18,000 feet into the Ellenberger Formation. Those making such claims assume there is a stainless steel plate, or plates, within the earth through which no liquid can possibly penetrate. That notion is not founded upon scientific fact. What is a fact is that the mantle of the earth contains millions and billions of natural fractures, caverns, recesses, faults, fissures and other migration pathways through which any liquid can seep and flow. These anomalies can carry liquids many miles vertically or horizontally.
Additionally, a pressure change in friction at a much higher level can result in much greater pressure increases at far greater depths resulting in an epicenter for fault slippage that is far below the area where the liquification and/or lubrication occurred. It is this lack of understanding about plate tectonics and earth movements that leads people to make false assumptions to support their rationalizations about events that they cannot explain in factual terms. Considering that one gallon of fresh water weights about 8.34 pounds, and considering the weight of solids, rock, metals and other naturally occurring elements in the crust and mantle of the earth, the amount of weight pushing downward, and being acted upon by barometric pressure at the surface, as well as all the weight of all we have built on the surface of the planet, the downward force acting upon plates at great depths is enormous. Reducing the friction that holds those plates in place can have catastrophic results.
Typically, earthquakes of less than 4.0 magnitude result in little or no damage to structures on the surface. Earthquakes greater than 4.0 can cause major problems like foundation damage to homes and commercial/industrial buildings that result in very costly repairs or, in a worst case scenario, result in buildings having to be condemned and demolished due to loss of structural integrity and the safety risk to humans that would ensue. But, the issue is really much greater than just structural damage. Even small earth movements can cause failures of casing pipes and cement on well pipes below the surface resulting in releases of toxic, carcinogenic, neurotoxic and radioactive contaminants into soil, groundwater, surface water and air. To prevent such results deep injection wells, in particular, need to be located far away from water, oil or gas wells that could be adversely affected by minor or major earth movements caused by sublimation brought on by liquification and/or lubrication that prompts earthquakes.
Unless one lives in an area of high earthquake activity that person probably does not have earthquake insurance for homes, commercial or industrial buildings, equipment, automobiles and other possessions that may be damaged or destroyed as a result of an earthquake, and that means a huge loss of out-of-pocket money to remediate damages suffered. Texas, being a state that is not known for earthquakes, is one place where almost nobody has earthquake insurance, and thus nobody is financially prepared for the potential losses that could be incurred if earthquakes cause property damage. Just repairing a damaged residential dwelling foundation can cost $10,000, or more.
Quoting from an SMU study of North Texas earthquake activity, "Were the DFW earthquakes natural or triggered by activities associated with natural gas production, most likely saltwater injection to dispose of brines? The spatial and time correlations are consistent with an induced or triggered source. Prior to 31 October 2008, there had been no local felt earthquakes known in Dallas and Tarrant Counties, which have been settled since about 1850. About seven weeks before the DFW quakes began, injection commenced in a SWD well only a few hundred meters from DFW epicenters and with an injection depth of 3.1-4.1 km. This approaches the 4.4-4.8 km we determined for the 11 earthquakes recorded by the SMU temporary local network. These earthquakes and the SWD well are within about 1 km of a mapped subsurface fault which trends in nearly the same direction as the alignment of epicenters. Fluid injections between 200,000 and 300,000 b/month into other faulted areas have triggered small earthquakes and are reported in the literature, recently in Paradox Valley Colorado. It is plausible that the fluid injection in the southwest SWD well could have affected the in-situ tectonic stress regime on the fault, reactivating it and generating the DFW earthquakes."
The Dallas-Fort Worth International Airport Board seemed to have little doubt about the correlation between toxic wastewater (saltwater, in industry parlance) disposal wells and earthquakes occurring under its runways from the disposal wells on airport property where Chesapeake Energy has drilled some 112 gas wells in the last few years. The Airport Board ordered those wells shut down in 2011, because they feared severe runway damage that could lead to a crash with many fatalities and infrastructure damage that would shut down one of the most important airports in the world. Closing DFW would have an enormously negative economic impact on the region, state, country and world because of its importance as a gateway for passenger travel, as well as its commercial cargo activity.
Looking at the bigger picture, earthquakes that might not cause significant property damage on the surface can cause casing pipe and cement failures below ground that result in contamination of groundwater and surface water reservoirs by releasing toxic, carcinogenic, neurotoxic and radioactive contaminants into surrounding subterranean strata, soil, air and water that results in human and animal health and safety issues and environmental pollution. Casing cement is a grout-like compound that has no structural strength, and which is easily broken by movement. It is a known and industry acknowledged fact that casing pipe and cement failures are responsible for the majority of groundwater contamination occurrences. Inducing ground moving stresses near casing pipes and cement could result in toxic fluid leaks, as well as explosions like the one that occurred in San Bruno, California in 2010, which resulted in 8 fatalities, 58 severe injuries, 38 homes being completely destroyed and another 120 home severely damaged.
In some areas there are other dangers and liabilities that most people have never even considered, and that is the potential for a disaster if drilling and frac'ing, or deep injection of wastewater, near dams on lakes and reservoirs causes ground subsidance resulting in earthquakes or sinkholes that erode a dam footing causing a failure of a dam or spillway. In the Dallas area Chesapeake and XTO have both drilled and frac'ed wells near and under Joe Pool Reservoir, a drinking water resource for Dallas and many surrounding cities. The Chesapeake Corn Valley A1H well sites just 850 feet north of the spillway and even closer to a large upper middle class neighborhood of $200-300,000 homes where several thousand people live. If a ground subsidance activity caused by an earthquake or sinkhole causes a dam failure in the middle of the night when people are at home asleep, then the results could be destruction of thousands of homes and the deaths of hundreds or thousands of people, as well as severe damage to roadways, electrical, water, sewer and other infrastructure that would severely cripple the area below the dam and spillway.
The US Army Corps of Engineers (USACE) has expressed its concerns about frac'ing near its dams and reservoirs to both drilling companies and local municipalities that are permitting, or considering permitting, gas exploration and production near Corps projects such as hydroelectric dams and drinking water reservoirs. Col. Richard J. Muraski, Jr, Former Commander of the Fort Worth Region of USACE, sent letters to the Cities of Grand Prairie and Dallas requesting moratoriums on drilling near the USACE dam at Joe Pool Reservoir after concerns were expressed by FracDallas Director Marc McCord and other citizens in 2010, though response has been slow from both the USACE and the cities.
The issue has also be raised in news stories published in the Dallas Morning News regarding the issues of ground subsidance, seismicity and fault slippage under the Joe Pool Dam as a result of frac'ing near the dam, which McCord first raised with the USACE in September, 2010, at which time he was told the issue had never been considered. In fact, the US Department of the Interior, Bureau of Land Management had addressed that very concern to the USACE and others are early as 1996 in a document titled Texas Resource Management Plan Record of Decision and Plan dated May 31, 1996, in which a 3,000 foot setback from any dam, spillway or other critical infrastructure of a USACE project was established. This requirement has not been enforced by the USACE, BLM, Department of the Interior or any city or municipality, including the City of Grand Prairie when it authorized Chesapeake Energy to drill its Corn Valley A1H well just 850 feet from the Joe Pool Reservoir spillway in 2010.
The Dallas-Fort Worth area is not known for earthquakes. In fact, until 2007, no earthquake had ever been recorded or observed in the DFW area or the surrounding Barnett Shale region of the state. As deep injection well activity has increased as the preferred disposal method of billions of gallons of flowback and produced wastewater from hydraulically fractured oil and gas wells the incidents of earthquakes in North Texas has begun and become much more prominent. In November, 2013, at least 18 earthquakes were recorded northwest of Fort Worth, home to about 2,000 active natural gas wells and several injection wells, including a magnitude 3.6 trembler on November 19, 2013, that have caused minor property damage such as foundation and wall cracks, but the larger concern is the safety of drinking warter reservoir dams and levees that retain hundreds of millions of gallons of water, and the possibility of casing pipe failures on active and inactive oil and gas wells leading to groundwater contamination.
The map at the right identifies the location of recent earthquakes and the larger map, viewed by clicking the map at the right, lists dates, locations and magnitudes for each of the recent earthquakes, all of which occurred very near active injection wells where recent injections were performed under the auspices and control of the Railroad Commission of Texas (RCT.) RCT has steadfastly refused to review and update its rules or act in the best interest of the health and safety of Texas citizens. Scientific studies by the US Geological Survey, University of Texas (Austin) Geophysical Sciences Department and Texas Christian University Geophysical Sciences Department have concluded that these earthquakes are most likely directly related to deep injection of wastewater, and they have demonstrated that earthquakes are occurring just days after injection sare performed. Of course, the RCT is led and staffed by people from the oil and gas industry, so they are not about to give an objective review of the situation and then act accordingly to protect the public. Instead, they protect the oil and gas industry and maintain the steady flow of cash contributions to their respective election campaigns so they can maintain the status quo for the oil and gas industry without regard to the damages caused to others.
Quoting from a StateImpact Texas article, "Teachers in the Azle school district are taking a page from the California playbook and holding earthquake drills for students. Inspectors are making regular visits to the earthen Eagle Mountain Lake dam, as well as others in the area, checking for damage." The article went on to state, "There were no quakes in the Dallas-Fort Worth and surrounding areas (including Azle) before 2007, according to records from the United States Geological Survey. But the region is part of the Barnett Shale, where the drilling process known as hydraulic fracturing, or "fracking," has taken off in recent years, leading some to question whether or not fracking is at fault." Scientists from USGS and several universities involved in earthquake research believe there is a cause-and-effect relationship between deep injection disposal wells and earthquakes near those sites.
This same issue exists in mountainous regions like Colorado, Utah, Idaho, Wyoming and other places where earthquakes could result in avalanches in winter that destroy winter recreation venues and the towns they support, again with a potential for substantial loss of human life and property damage. Those arguing in favor of drilling and deep injection disposal of wastewater will cite the small number of times when such problems occur, but if you are one of those who is injured, killed, incurs a property loss or whose family members or friends are victims of such tragedies, then that one incident becomes important and catastrophic. Yet, industry and government regulators seem oblivious to the potential and disinterested in even considering the possibility that such a disaster could occur.
So, again we ask, can hydraulic fracturing operations (including deep injection disposal wells) cause earthquakes? Yes! Have such earthquakes been documented by the USGS and major university research departments? Yes! Is there a very real potential for death, injury and property destruction resulting from earthquakes associated with natural gas exploration and production? Yes! Can such potential disasters be mitigated or prevented? Yes! If industry would voluntarily agree to locate disposal wells far away from production wells, geological fault lines, drinking water reservoirs, lakes, mountains, inhabited areas and take other prudent steps to protect people and property from the adverse effects of their heavy industrial process, then they would find a lot less opposition to their activities. And, if industry would cease trying to drill and frac the entire planet, and would conscientiously avoid activities in sensitive areas where such disasters could potentially occur, then they would find a lot less opposition to their activities.
Unfortunately, the oil and gas industry does whatever it is allowed to do, legally or illegally, and state and federal regulators are failing to do their jobs in enforcing codes, laws and regulations that hold industry accountable for their violations due to lack of funding, insufficient staffing, lack of knowledge about how to regulate, or a willful blind eye toward an industry that too many people believe should have few regulations so that they can provide us with cheap, domestic energy even if it does risk the health and safety, property values and environment of citizens who lack the money and political power to fight against the industry through a legal system that is stacked against citizens and in favor of that industry. A major disaster will probably be required to get the attention of the public and our elected officials, but then again we seem to have learned very little from Exxon Valdez or the BP Gulf oil spill.
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