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AG Pruitt testifies before a congressional committee on issues surrounding energy and the environment

“Polluting Pruitt:” A Wolf to Guard the Hen House?

Guest article by Dakota Raynes, Co-Organizer of Stop Fracking Payne County (OK)

President Trump recently tapped Oklahoma Attorney General Scott Pruitt to head the Environmental Protection Agency (EPA), even though Pruitt is a self-proclaimed “leading advocate against the EPA’s activist agenda.” Pruitt is currently opposing investigation of Exxon Mobile’s handling of climate-change science based on the belief that climate change science is not yet settled and “debate should be encouraged in classrooms, public forums, and the halls of Congress.” Senate confirmation hearings regarding Pruitt’s nomination are currently ongoing – many questions have focused on Pruitt’s legacy as AG of OK and what that tells us about actions he might take as head of the EPA.

Pruitt’s Past as AG

Elected in 2010, Pruitt’s six-year tenure illuminates the full extent of the troubling stances he takes. For instance, he has fought against the overturn of DOMA, same-sex marriage rights, granting legal status to undocumented immigrants, the Affordable Care Act, access to safe and affordable birth control and abortions, and Dodd-Frank Wall Street reform. These actions demonstrate Pruitt’s inability to accept or implement procedures, policies, and programs supported by a majority of US residents, members of the nations’ highest courts, and even his own colleagues.

A Focus on Environmental Issues

More specifically related to environmental issues, he has openly criticized the EPA in congressional hearings and op-ed pieces. Due to his belief that the EPA frequently abuses its authority, Pruitt’s office has filed 14 antiregulatory lawsuits against the EPA. Investigative reporters uncovered that in 13 of these cases co-litigators included companies that had contributed significant amounts of money to Pruitt and/or Pruitt-affiliated political action committees (PACs). He also routinely joins lawsuits against other states. For example, Pruitt and five other Attorneys General challenged a California law banning the sale of eggs laid by hens living in cramped conditions, but a US District Judge ruled they lacked legal standing because they were representing the economic interests of a few industrial egg producers rather than the interests of their broader constituents.

Several such lawsuits are still pending, which legal experts and others claim presents a conflict of interest should Pruitt become the new Director of the EPA. When asked specifically about this issue during Senate confirmation hearings, Pruitt refused to recuse himself from the lawsuits, saying he would leave such a decision up to the EPA’s legal counsel team. Notably, across the course of his six-years as AG, Pruitt’s office has distributed more than 700 news releases announcing the office’s actions, his speeches and public appearances, and efforts to challenge federal regulations. More than 50 of these releases promoted the office’s efforts to sue the EPA, but not once has a release described actions the office has taken to enforce environmental laws or to hold violators accountable for their actions.

Potential Conflicts of Interest

In OK, Pruitt has made many choices, that when viewed together, strongly suggest that his loyalties reside with the industries that have donated hundreds of thousands of dollars to his election campaigns rather than with the people he is sworn to protect. Here is a short list of the most troubling examples:

  • Pruitt’s predecessor had filed suit against Tyson, Cargill, and a number of other poultry producers in OK due to inappropriate disposal of an estimated 300,000 tons of animal waste per year, which was causing toxic algae blooms along the Illinois River. But shortly after his election, Pruitt dropped the case, citing a need for more research. Some have questioned whether his decision was impacted by the fact that the poultry industry had donated at least $40,000 to his campaign that year.
  • He also quickly dismantled the Attorney General’s in-house environmental protection unit, a team of four attorneys and a criminal investigator, and replaced it with the state’s first “federalism unit,” which was created to litigate against overreach by the federal government, mostly the EPA. Pruitt has repeatedly made it clear that he believes states should handle environmental issues, regardless of the fact that environmental issues frequently cause problems that cross geopolitical boundaries such as state lines (OK’s induced seismicity issue1 is a key example, more information about induced seismicity can be found here).
  • In 2013, he created a coalition of 9 Attorneys General, major energy CEOs, and their lawyers and brought them all to OK for a strategizing session regarding how to stop government and citizen responses to the ills of the oil and gas industry; it was an all-expenses paid event funded by Mercatus, a right-wing think tank favored by the Koch brothers.
    1. Notably, the energy industry is Pruitt’s second largest campaign contributor. When he came up for re-election in 2013, he chose Harold Hamm (CEO of Continental Resources, one of the largest oil companies in OK) to co-chair his campaign. Shortly after winning reelection in 2014, Pruitt joined forces with key industry players including Oklahoma Gas and Electric and the Domestic Energy Producers Alliance (chaired by Hamm) to file several antiregulatory lawsuits, which include attempts to block the Clean Power Plan and Waters of the US rule.
    2. Pruitt has also served as leader of the Republican Association of Attorneys General, which has collected at least $4.2 million in donations from fossil-fuel related companies since 2013.
  • Recently, local investigative reporters discovered that Pruitt’s office failed to follow a state law requiring state agencies to disclose spending on outside attorneys. Their examination illuminated that Pruitt has spent more than $1 million on legal fees since FY2012 – a total that does not include costs directly related to lawsuits against the EPA or the Affordable Care Act.

Induced-Seismicity and Wastewater Disposal

OK Map of Recent Earthquakes for Pruitt article

Map of Oklahoma Class II Injection Wells and Volumes 2011 to 2015 (Barrels). Click image to explore a full screen, dynamic map.

Oklahoma recently became the earthquake capital of the world due to a phenomenon referred to as injection-induced seismicity. While OK has not historically been known as a seismically active area, thousands of tremors have shaken the state since the shale gas boom began.

Several researchers have used geospatial analysis to demonstrate how these quakes are caused by the high-pressure injection of oil and gas industry wastes such as the flowback and produced water created by the unconventional oil and gas production process known as hydraulic fracturing. The map above shows where injection wells (tan dots) are located and where earthquakes (green dots) occurred from 2011-2015.

Oklahomans have been harmed by the implicitly pro-fracking stance Pruitt has taken, as evidenced by his lack of action regarding induced seismicity – as well as air, water, and soil contamination due to oil and gas industry activities. Several people, including Johnson Bridgewater (Director of OK Chapter of the Sierra Club) have noted that:

There are various places where the attorney general’s office could have stepped in to fix this overall problem…Its job is to protect citizens. Other states were proactive and took these issues on…[yet] Pruitt has been completely silent in the face of a major environmental problem for the state and its taxpayers.

Specifically, the AG’s office could have responded to the legal question of whether the state could limit or ban transport of fracking-related wastewater, sent by other states for disposal in underground injection wells in OK.

He also did nothing to address the phenomenally low earthquake insurance claim approval rate; after the 5.8M quake shook Pawnee in September of 2016, 274 earthquake damage claims were filed but only 4 paid out. Estimates of statewide approval rates generally suggest that approximately 1% of claimants receive funds to aid repairs.

Lastly, there are a number of class action lawsuits against a variety of industry actors regarding earthquake damages, yet Pruitt’s office has not entered any of these as an intervenor even though AGs in other states have done so.

Pruitt not at fault?

Photo Credit: JIM BECKEL/The Oklahoman

Earthquake damage. Photo Credit: Jim Beckel/The Oklahoman

Pruitt was recently called out by investigative reporters who used open-records requests to reveal that letters, briefs, and lawsuits that he submitted were written in whole or in part by leading energy firms such as Devon (another of OK’s largest oil and gas companies). Pruitt’s response was that he had done nothing wrong, nothing even potentially problematic. Rather, he said, of course he was working closely with industry and isn’t that what he should be doing. Some would argue that as AG what he should be doing is working closely with the people of Oklahoma, especially those whose homes, lives, and livelihoods have crumbled under the weight of attempting to repair earthquake damage due to industry activities.

Historical AG Influence

It is important to remember, though, that what’s happening with Pruitt is not isolated. Rather, as several long-time reporters have noted, increased attention to developing beneficial relationships with AGs is a result of historical processes.

About 20 years ago more than 40 state AGs banded together to challenge the tobacco industry, which led to a historic $206 billion settlement decision. Later, Microsoft, the pharmaceutical industry, and the financial services industry each faced similar multistate challenges regarding the legality or illegality of particular business practices.

As some AGs began hiring outside law firms to investigate and sue corporations, industry leaders realized that AGs’ actions were far more powerful and immediate than those of legislative bodies. So, they began a heretofore unprecedented campaign to massively increase their influence at this level.

Several people have critiqued the ways in which such actions undermine democratic processes, prompt troubling questions about ethics, and negatively impact attorney generals’ abilities to fulfill their duties to the state and its residents.

A Mission at Risk

Those of us on the frontlines here in OK have seen just how powerful such coalitions can be, how much sway they can have on local and state officials, how they destabilize people’s faith and trust in the systems that are supposed to protect them, and how coalitions undercut people’s hope and desire to be civically engaged. The mission of the US Environmental Protection Agency is to protect human health and the environment. If confirmed to lead the EPA, it is very likely Pruitt will prioritize his relationships with industry over the health and welfare of the people and environment he’s directed to protect.

Footnotes

  1. To learn more about induced seismicity read an exclusive FracTracker two-part series from former VTSO researcher Ariel Conn: Part I and Part II. Additionally, the USGS has created an Induced Earthquakes landing page as part of their Earthquake Hazards Program.
Northeast Ohio Class II injection wells taken via FracTracker's mobile app, May 2015

OH Class II Injection Wells – Waste Disposal and Industry Water Demand

By Ted Auch, PhD – Great Lakes Program Coordinator

Waste Trends in Ohio

Map of Class II Injection Volumes and Utica Shale Freshwater Demand in Ohio

Map of Class II Injection Volumes and Utica Shale Freshwater Demand in Ohio. Explore dynamic map

It has been nearly 2 years since last we looked at the injection well landscape in Ohio. Are existing disposals wells receiving just as much waste as before? Have new injection wells been added to the list of those permitted to receive oil and gas waste? Let’s take a look.

Waste disposal is an issue that causes quite a bit of consternation even amongst those that are pro-fracking. The disposal of fracking waste into injection wells has exposed many “hidden geologic faults” across the US as a result of induced seismicity, and it has been linked recently with increases in earthquake activity in states like Arkansas, Kansas, Texas, and Ohio. Here in OH there is growing evidence – from Ashtabula to Washington counties – that injection well volumes and quarterly rates of change are related to upticks in seismic activity.

Origins of Fracking Waste

Furthermore, as part of this analysis we wanted to understand the ratio of Ohio’s Class II waste that has come from within Ohio and the proportion of waste originating from neighboring states such as West Virginia and Pennsylvania. Out of 960 Utica laterals and 245+ Class II wells, the results speak to the fact that a preponderance of the waste is coming from outside Ohio with out-of-state shale development accounting for ≈90% of the state’s hydraulic fracturing brine stream to-date. However, more recently the tables have turned with in-state waste increasing by 4,202 barrels per quarter per well (BPQPW). Out-of-state waste is only increasing by 1,112 BPQPW. Such a change stands in sharp contrast to our August 2013 analysis that spoke to 471 and 723 BPQPW rates of change for In- and Out-Of-State, respectively.

Brine Production

Ohio Class II Injection Well trends In- and Out-Of-State, Cumulatively, and on Per Well basis (n = 248).

Figure 1. Ohio Class II Injection Well trends In- and Out-Of-State, Cumulatively, and on Per Well basis (n = 248).

For every gallon of freshwater used in the fracking process here in Ohio the industry is generating .03 gallons of brine (On average, Ohio’s 758 Utica wells use 6.88 million gallons of freshwater and produce 225,883 gallons of brine per well).

Back in August of 2013 the rate at which brine volumes were increasing was approaching 150,000 BPQPW (Learn more, Fig 5), however, that number has nearly doubled to +279,586 BPQPW (Note: 1 barrel of brine equals 32-42 gallons). Furthermore, Ohio’s Class II Injection wells are averaging 37,301 BPQPW (1.6 MGs) per quarter over the last year vs. 12,926 barrels BPQPW – all of this between the initiation of frack waste injection in 2010 and our last analysis up to and including Q2-2013. Finally, between Q3-2010 and Q1-2015 the exponential increase in injection activity has resulted in a total of 81.7 million barrels (2.6-3.4 billion gallons) of waste disposed of here in Ohio. From a dollars and cents perspective this waste has generated $2.5 million in revenue for the state or 00.01% of the average state budget (Note: 2.5% of ODNR’s annual budget).

Freshwater Demand Growing

Ohio Class II Injection Well disposal as a function of freshwater demand by the shale industry in Ohio between Q3-2010 and Q1-2015.

Figure 2. Ohio Class II Injection Well disposal as a function of freshwater demand by the shale industry in Ohio between Q3-2010 and Q1-2015.

The relationship between brine (waste) produced and freshwater needed by the hydraulic fracturing industry is an interesting one; average freshwater demand during the fracking process accounts for 87% of the trend in brine disposal here in Ohio (Fig. 2). The more water used, the more waste produced. Additionally, the demand for OH freshwater is growing to the tune of 405-410,000 gallons PQPW, which means brine production is growing by roughly 12,000 gallons PQPW. This says nothing for the 450,000 gallons of freshwater PQPW increase in West Virginia and their likely demand for injection sites that can accommodate their 13,500 gallons PQPW increase.

Where will all this waste go? I’ll give you two guesses, and the first one doesn’t count given that in the last month the ODNR has issued 7 new injection well permits with 9 pending according to the Center For Health and Environmental Justice’s Teresa Mills.

Earthquake damage photo from Wikipedia

The Science Behind OK’s Man-made Earthquakes, Part 2

By Ariel Conn, Seismologist and Science Writer with the Virginia Tech Department of Geosciences

Oklahoma has made news recently because its earthquake story is so dramatic. The state that once averaged one to two magnitude 3 earthquakes per year now averages one to two per day. This same state, which never used to be seismically active, is now more seismically active than California. In terms of understanding the connection between wastewater disposal wells and earthquakes, though, it may be more helpful to look at other states first. Let us explore this issue further in Man-made Earthquakes, Part 2.

How other states handle induced seismicity

In 2010 and 2011, Arkansas experienced a swarm of earthquakes near the town of Greenbrier that culminated in a magnitude 4.7 earthquake. Officials in Arkansas ordered a moratorium on all disposal wells in the area, and earthquake activity quickly subsided.

In late 2011, Ohio experienced small earthquakes near a disposal well that culminated in a magnitude 4 earthquake that shook and startled residents. The disposal well was shut down, and the earthquakes subsided. Subsequent research into the earthquake confirmed that the disposal well in question had, in fact, triggered the earthquake. A swarm of earthquakes last year in Ohio shut down another well, and again, after the wastewater injection ceased, the earthquakes subsided.

Similarly in Kansas, after two earthquakes of magnitudes 4.7 and 4.9 shook the state in late 2014, officials ordered wells in two southern counties to decrease the volume of water injected into the ground. Again, earthquake activity quickly subsided.

A seismologist’s toolbox

A favorite saying among scientists is that correlation does not equal causation, and it’s easy to apply that phrase to the correlations seen in Ohio, Arkansas, and Kansas. Yet scientists remain certain that wastewater disposal wells can trigger earthquakes. So what are some of the techniques they use to come to these conclusions? At the Virginia Seismological Observatory (VTSO), two of the tools we used to determine a connection were cross-correlation programs and beach ball diagrams.

Cross-correlation

The VTSO research, which was funded by the National Energy Technology Laboratory, looked specifically at earthquake swarms that have popped up a couple times near a wastewater disposal well in West Virginia. We used a cross-correlation program to distinguish earthquakes that were likely triggered by the nearby well from events that might be natural or related to mining activity.

A seismic station records all of the vibrations that occur around it as squiggly lines. When an earthquake wave passes through, its squiggly lines take on a specific shape, known as a waveform, that seismologists can easily recognize (as an example, the VTSO logo in Fig. 1 was designed using a waveform from one of West Virginia’s potentially induced earthquakes.)

Virginia Tech Seismological Observatory logo

Figure 1. Virginia Tech Seismological Observatory logo w/waveform

For naturally occurring earthquakes, the waveforms will have some variation in shape because they come from different faults in different locations. When an injection well triggers earthquakes, it typically activates faults that are within close proximity, resulting in greater similarities between waveforms. A cross-correlation program is simply a computer program that can run through days, weeks, or months of data from a seismometer to find those similar waveforms. When matching waveforms indicate that earthquake activity is occurring near an injection well – and especially in regions that don’t have a history of seismic activity – we can conclude the earthquakes are triggered by human activity.

Beach Balls

Any earthquake fault, whether it’s active or ancient, is stressed to its breaking point. The difference is that, in places like California that are active, the natural forces against the faults often change, which triggers earthquakes. Ancient faults are still highly stressed, but the ground around them has become more stabilized. However at any point in time, if an unexpected force comes along, it can still trigger an earthquake.

Beach ball diagrams of 16 of the largest earthquakes in Oklahoma in 2014, all showing similar focal mechanisms, which is indicative of induced seismicity.

Figure 2. Beach ball diagrams of 16 of the largest earthquakes in Oklahoma in 2014, all showing similar focal mechanisms, which is indicative of induced seismicity.

Earthquake faults don’t all point in the same direction, which means different forces will affect faults differently. Depending on their orientation, some faults might shift in a north-south direction, some might shift in an east-west direction, some might be tilted at an angle, while others are more upright, etc. Seismologists use focal mechanisms to describe the movement of a fault during an earthquake, and these focal mechanisms are depicted by beach ball diagrams (Figure 2). The beach ball diagrams look, literally, like black and white beach balls. Different quadrants of the “beach ball” will be more dominant depending on what type of fault it was and how it moved (See USGS definition of Focal Mechanisms and the “beach ball” symbol).

When an earthquake is triggered by an injection well, it means that the fluid injected into the ground is essentially the straw that broke the camel’s back. Earthquake theory predicts that the forces from an injection well won’t trigger all faults, but only those that are oriented just right. Since we expect that only certain faults with just the right orientation will get triggered, that means we also expect the earthquakes to have similar focal mechanisms, and thus, similar beach ball diagrams. And that’s exactly what we see in Oklahoma.

Cross-correlation programs and beach ball diagrams are only two tools we used at the VTSO to confirm which earthquakes were induced, but seismologists have many means of determining if an earthquake is induced or natural.

Limitations of science?

With so much strong scientific evidence, why can people in industry still claim there isn’t enough science to officially confirm that an injection well triggered an earthquake? In some cases, these claims are simply wrong. In other cases, though, especially in Oklahoma, the problem is that no one was monitoring the disposal wells and the earthquakes from the start. Well operators were not required to publicly track the volumes of water they injected into wells until recently, and no one monitored for nearby earthquake activity. The big problem is not a lack of scientific evidence, but a lack of data from industry to perform sufficient research. Scientists need information about the history, volume, and pressure of fluid injection at a disposal well if they’re to confirm whether or not earthquakes are triggered by it. Often, that information is proprietary and not publically available, or it may not exist at all.

At this point though, two other factors make direct correlations between injection wells and earthquakes in Oklahoma even more difficult:

  1. So many wells have injected signficiant volumes of water in close enough proximity that pointing a finger at a specific well is more challenging.
  2. A large number of wells have injected water for so many years, that the earthquakes are migrating farther and farther from their original source. Again, pointing a finger at a specific well gets harder with time.

What we know

We know what induced seismicity is and why it occurs. We know that if a wastewater injection well disposes of large volumes of fluids deep underground in a region that has existing faults, it will likely trigger earthquakes. We know that if a region previously had few earthquakes, and then sees an uptick in earthquakes after wastewater injection begins, the earthquakes are likely induced. We know that if we want to understand the situation better, we need more seismic stations near disposal wells so we can more accurately monitor the area for seismicity both before and after the well becomes active.

What don’t we know?

We don’t know how big an induced earthquake can get. Oklahoma’s largest earthquake, which was also the largest induced earthquake ever recorded in the United States, was a magnitude 5.6. That’s big enough to cause millions of dollars of damage. Worldwide, the largest earthquake suspected to be induced occurred near the Koyna Dam in India, where a magnitude 6.3 earthquake killed nearly 200 people in 1967.

Can an earthquake that large occur in the central U.S.? The best guess right now: yes.

Seismologists suspect that an induced earthquake could get as big as the size of the fault. If a fault is big enough to trigger a magnitude 7 or 8 earthquake, then that is potentially how large an induced earthquake could be. In the early 1800s, three earthquakes between magnitudes 7 and 8 struck along the New Madrid Fault Zone near St. Louis, Missouri. Toward the end of the 1800s, a magnitude 7 earthquake shook Charleston, South Carolina. In those two areas, injection wells could potentially trigger very large earthquakes.

We have no historic record of earthquakes that large in Oklahoma, so right now, the best guess is that the largest an earthquake could get there would be between a magnitude 6 and 6.5. That would be big enough to cause significant damage, injuries, and possibly death.

The solution

What’s the take-home message from all of this?

  • First, the science exists to back up the conclusion that wastewater injection wells trigger earthquakes.
  • Second, if we want to get a better feel for which wells are more problematic, we need funding, seismic stations, and staff to monitor seismic activity around all high-volume injection wells, along with a history of injection times, volumes and pressures at the well.
  • Third, this is a problem that, if left unchecked, has the potential to result in major damage, incredible expense, and possibly loss of life.

Induced earthquakes are a real phenomenon. While more research is necessary to help us better understand the intricacies of these events and to identify correlations in complex cases, the general cause of the earthquake swarms in Oklahoma and other states is not a mystery. They are man-made problems, backed up by decades of scientific research. They have the potential to create significant damage, but we have the wherewithal to prevent them. We don’t need to go to the extreme of shutting down all wells, but rather, we just need to be able to monitor the wells and ensure that they don’t trigger earthquakes. If a well does trigger an earthquake, then at that point, the well operators can either experiment with significantly decreasing the volume of water that’s injected, or the well can be shut down completely. Understanding and acknowledging the connection between injection wells and earthquakes will make induced seismicity a much easier problem to solve.

The Science Behind OK’s Man-made Earthquakes, Part 1

By Ariel Conn, Seismologist and Science Writer with the Virginia Tech Department of Geosciences

On April 21, the Oklahoma Geological Survey issued a statement claiming that the sharp rise in Oklahoma earthquakes — from only a couple per year to thousands — was most likely caused by wastewater disposal wells associated with major oil and gas plays. This is huge news after years of Oklahoma scientists hesitating to place blame on an industry that provides so many jobs.

Now, seismologists from around the country — including Oklahoma — are convinced that these earthquakes are the result of human activity, also known as induced or triggered seismicity. Yet many people, especially those in the oil industry, still refute such an argument. Just what is the science that has seismologists so convinced that the earthquakes are induced and not natural?

Hidden Faults

Over the last billion years (give or take a couple hundred million), colliding tectonic plates have created earthquake zones, just as we see today in California, Japan, Chile and Nepal. As geologic processes occurred, these zones shifted and moved and were covered up, and the faults that once triggered earthquakes achieved a state of equilibrium deep in the basement rocks of the earth’s crust. But the faults still exist. If the delicate balance that keeps these fault systems stable ever shifts, the ancient faults can still move, resulting in earthquakes. Because these inactive faults are so deep, and because they can theoretically exist just about anywhere, they’re incredibly difficult to map or predict – until an earthquake occurs.

Thanks to historic reports of earthquakes in the central and eastern United States, we know there are some regions, far away from tectonic plate boundaries, that occasionally experience large earthquakes. Missouri and South Carolina, for example, suffered significant and damaging earthquakes in the last 200 hundred years, yet these states lie nowhere near a plate boundary. We know that fault zones exist in these locations, but we have no way of knowing about dormant faults in regions of the country that haven’t experienced earthquakes in the last couple hundred years.

What is induced seismicity?

As early as the 1930s, seismologists began to suspect that extremely large volumes of water could impact seismic activity, even in those regions where earthquakes weren’t thought to occur. Scientists found that after certain reservoirs were built and filled with water, earthquake swarms often followed. This didn’t happen everywhere, and when it did, the earthquakes were rarely large enough to be damaging. These quakes were large enough to be felt, however, and they represented early instances of human activity triggering earthquakes.[1]

Research into induced seismicity really picked up in the 1960s. The most famous example of man-made earthquakes occurred as a result of injection well activity at the Rocky Mountain Arsenal. The arsenal began injecting wastewater into a disposal well 12,000 feet deep in March of 1962, and by April of that year, people were feeling earthquakes. Researchers at the arsenal tracked the injections and the earthquakes. They found that each time the arsenal injected large volumes of water (between 2 and 8 million gallons per month, or 47,000 to 190,000 barrels), earthquakes would start shaking the ground within a matter of weeks (Figure 1).

Rocky Mountain Arsenal fluid injection correlated to earthquake frequency

Figure 1. Rocky Mountain Arsenal fluid injection correlated to earthquake frequency

South Carolina experienced induced earthquakes after filling a reservoir

Figure 2. South Carolina experienced induced earthquakes after filling a reservoir

When the injections ended, the earthquakes also ceased, usually after a similar time delay, but some seismicity continued for a while. The well was active for many years, and the largest earthquake thought to be induced by the injection well actually occurred nearly a year and a half after injection officially ended. That earthquake registered as a magnitude 5.3. Scientists also noticed that over time, the earthquakes moved farther and farther away from the well.

Research at a reservoir in South Carolina produced similar results; large volumes of water triggered earthquake swarms that spread farther from the reservoir with time (Figure 2).

When people say we’ve known for decades that human activity can trigger earthquakes, this is the research they’re talking about.

Why now? Why Oklahoma?

Class II Injection Well. Photo by Lea Harper

Injection Well in Ohio. Photo by Ted Auch

Seismologists have known conclusively and for quite a while that wastewater injection wells can trigger earthquakes, yet people have also successfully injected wastewater into tens of thousands of wells across the country for decades without triggering any earthquakes. So why now? And why in Oklahoma?

The short answers are:

  • At no point in history have we injected this much water this deep into the ground, and
  • It’s not just happening in Oklahoma.

One further point to clarify: General consensus among seismologists is that most of these earthquakes are triggered by wastewater disposal wells and not by hydrofracking (or fracking) wells. That may be a point to be contested in a future article, but for now, the largest induced earthquakes we’ve seen have been associated with wastewater disposal wells and not fracking. This distinction is important when considering high-pressure versus high-volume wells. A clear connection between high-pressure wells and earthquakes has not been satisfactorily demonstrated in our research at the Virginia Tech Seismological Observatory (VTSO) (nor have we seen it demonstrated elsewhere, yet). High-volume wastewater disposal wells, on the other hand, have been connected to earthquakes.

At the VTSO, we looked at about 8,000 disposal wells in Oklahoma that we suspected might be connected to induced seismicity. Of those, over 7,200 had maximum allowed injection rates of less than 10,000 barrels per month, which means the volume is low enough that they’re unlikely to trigger earthquakes. Of the remaining 800 wells, only 300 had maximum allowed injection rates of over 40,000 barrels per month — and up to millions of barrels per year for some wells. These maximum rates are on par with the injection rates seen at the Rocky Mountain Arsenal, and our own plots indicate a correlation between high-volume injection wells and earthquakes (Figure 3-4).

Triangles represent wastewater injection wells scaled to reflect maximum volume rates. Wells with high volumes are located near earthquakes.

Figure 3. Triangles represent wastewater injection wells scaled to reflect maximum volume rates. Wells with high volumes are located near earthquakes.

Triangles represent wastewater injection wells scaled to reflect maximum pressure. Wells with high pressures are not necessarily near earthquakes.

Figure 4. Triangles represent wastewater injection wells scaled to reflect maximum pressure. Wells with high pressures are not necessarily near earthquakes.

This does not mean that all high-volume wells will trigger earthquakes, or that lower-volume wells are always safe, but rather, it’s an important connection that scientists and well operators should consider.

Starting in 2008 and 2009, with the big oil and gas plays in Oklahoma, a lot more fluid was injected into a lot more wells. As the amount of fluid injected in Oklahoma has increased, so too have the number of earthquakes. But Oklahoma is not the only state to experience this phenomenon. Induced earthquakes have been recorded in Arkansas, Colorado, Kansas, New Mexico, Ohio, West Virginia and Texas.

In the last four years, Arkansas, Kansas, Ohio and Texas have all had “man-made” earthquakes larger than magnitude 4, which is the magnitude at which damage begins to occur. Meanwhile, in that time period, Colorado experienced its second induced earthquake that registered larger than magnitude 5. Oklahoma may have the most induced and triggered earthquakes, but the problem is one of national concern.

Footnote

[1] Induced seismicity actually dates back to the late 1800s with mining, but the connection to high volumes of fluid was first recognized in the 1930s. However, the extent to which it was documented is unknown.