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Wicked Witch of the Waste

The Great Plains has become the unconventional oil & gas industry’s dumping ground, prompting questions about the security and resilience of the bread basket and the underlying Ogalalla Aquifer

Back in December of 2016, FracTracker analyzed the growing link between injection wells that dispose fracking waste and “induced seismicity” [1], or human-caused earthquakes. Our compiled maps from this analysis (including Figure 1 below) show seismic activity in Kansas and Oklahoma along with Class II injection well volumes up through 2015. 

Figure 1. Earthquakes and Class II Injection Well Activity at the Kansas-Oklahoma Border

This link was given acute attention at that time as a result of the magnitude 5.8 earthquake in Pawnee, Oklahoma on September 3rd, 2016, followed closely by a 4.5 earthquake on November 1st.  The industry’s increased production of waste came home to roost 5 days later when a magnitude 5.0 quake struck a mile west of the “Cushing Hub,” the largest commercial crude oil storage center in North America. The Cushing Hub is capable of storing 54 million barrels of crude – the equivalent of 2.8 times the U.S. daily oil refinery capacity and 3.1 times the daily oil refinery capacity of all of North America.

Sunflower State of Affairs

Since we published this analysis and associated maps, Class II injection wells have been in the news several times across the Great Plains. An investigation by KSN News found that the Kansas Corporation Commission (KCC) improperly permitted over 2,000 Class II injection wells. The KCC stated that public comment periods for well proposals lasted just 15 days, instead of the correct number of 30 days. This amounts to 42% and 28% of the state’s active and total inventory of oil and gas waste receiving wells approved with inaccurate public notices.


Quail Oil & Gas LC’s Class II Salt Water Disposal (SWD) well, Morris County,
KS near Diamond Creek (Photo Courtesy of Karla jo Grimmett at South 500 photography)

According to Cindy Hoedel, a freelance journalist in Kansas, the KCC responded to the investigation findings… by ruling that no remedy was needed and closing the docket.”

Attorneys representing the Sierra Club maintain that improper permitting by the KCC continued into the Fall of 2018:

“The significance is they are choking us off in terms of giving us less and less time to try to mount a protest, to submit any kind of comment, and that’s a lot,” Cindy Hoedel, a Matfield Green resident who has complained about earthquakes in her area, said… “These notices get published in these tiny little newspapers, and sometimes it might take us 15 days before we find it”

As Ms. Hoedel wrote in an email when I asked her to comment on issues relating to Kansas’ Class II injection wells:

“The Republican controlled Kansas Legislature is trying to fend off several proposed bills that would reform the KCC (the regulatory body that oversees the permitting of Class II underground injection control wells). Citizen challenges of individual applications for disposal and EOR [enhanced oil recovery] wells continue, with the KCC moving more aggressively than in the past to dismiss protestants before a hearing is held. Some of these dismissals are being challenged in appellate court. The activists’ view is that EPA, the SWDA [Safe Water Drinking Act] and Congress clearly intend for the public to be able to participate in the regulatory process; instead, KCC has written regulations that are effectively barriers to participation… Activists have questions about the large number of EOR wells being applied for in Kansas and what their true purpose is, given the insignificant amounts of oil being produced compared to high volumes of injected fluids. Another concern is that the injection well earthquakes in Oklahoma and Kansas continue, yet KCC refuses to add regs that would address seismic risk in permit applications. There is also a problem with harassment of citizens exercising their right to protest – Scott Yeargain and I were both turned in to the Kansas AG’s office by a KCC staffer on the bogus claim that we were practicing law without a license because we helped explain the convoluted process to other protesters.”

Grapes of Wrath

Meanwhile, across the border, Oklahoma City and its surrounding suburbs have become the San Francisco of the Great Plains, with regular earthquake swarms (including many that exceed magnitude 4.0). According to Think Progress reporter Samantha Page, despite the damages and lawsuits caused by these earthquakes, “for years, the state was slow to respond, while Gov. Mary Fallin (R) and others questioned the link to human activity.” 

Eventually, by the end of 2016, the Oklahoma Corporation Commission responded by implementing a ‘traffic light’ protocol, in which operations are paused or stopped altogether following earthquakes of certain magnitudes. For a time, the EPA demanded a moratorium on disposal across Class II wells injecting into the Arbuckle formation in “high seismically active focus areas.”

Chad Warmington, president of the Oklahoma Oil and Gas Association, said that this response by the EPA is “a stellar example of the inefficiency of the federal government…It’s akin to a newspaper telling us today the football scores from games played 15 months ago.”

In reporting on the industry’s response, journalist Paul Monies, buried the lead when he pointed out the following in his second to last paragraph:

“Wastewater recycling remains an expensive option compared to the low costs of disposal wells in Oklahoma. While operators can inject wastewater into formations other than the Arbuckle, Hatfield said other formations don’t accept water as easily and are at shallower depths.”

The Map

Our second stab at mapping the scale and scope of Class II injection wells across the Great Plains is slightly different than our first effort in a few ways:

  1. This iteration includes Class II Salt Water Disposal (SWD) Injection Wells in Nebraska, Oklahoma, and Kansas on one map. Clicking on a well reveals its location, well name, operator, and the volume of wastewater disposed. Volumes are presented annually for Nebraska and monthly for 2011 to 2017 for Oklahoma and Kansas. We also present annual sums for Oklahoma from 2006 to 2010.
  2. The map shows Arkansas and Platte River Basin boundaries, which contain the entire inventory of OK, NE, and KS Class II wells.
  3. We’ve included Hydrologic Unit Codes, which when zoomed in to the map, identify sub-watersheds, and the Ogalalla Aquifer boundary, courtesy of the USGS’s Sharon Qi.
  4. Finally, we’ve includedUS Forest Service Robert G. Bailey’s Ecoregions to give a sense for the types of ecosystems threatened by the O&G industry’s demand for suitable waste disposal sites

View Map Full Screen | To view the legend on this map, click the “layers” icon on the top left of the screen


Table 1, below, breaks down the volumes of oil and gas wastewater disposed in Oklahoma, Kansas and Nebraska. Volumes are measured in million barrels, with one barrel equivalent to 42 gallons. The number of Class II SWD (salt water disposal) injection wells in these states is separated to show the total number of wells permitted verse the number of wells that were active (receiving waste).

Table 1. Class II injection well volumes in 2017

In total, 3,385,700,000 barrels of wastewater were disposed in 5,975 injection wells in these three states in 2017. The volume of wastewater disposed has increased in recent years (Table 2).

Table 2. Cumulative Class II injection well volumes to 2017, annual percent changes, and likely 2018 and 2027 volumes

In Table 2, the theoretical annual volumes for 2018 and 2027 are predictions based on the average of linear, exponential, and polynomial models.

The Kansas-Oklahoma Border

It is critical that we analyze the Great Plains fracking waste ecosystem across state lines. There are several reasons for this, including the proximity of Kansas’ most active Class II wells to the Oklahoma border (Figure 2) and the potential for the KCC to use enhanced oil recovery wells in Kansas to dispose of Oklahoma’s fracking waste.

Figure 2. Class II injection well volumes for 2017 along the Kansas-Oklahoma border.

Collaboration between front line communities, non-profits like FracTracker Alliance, and groups like the Kansas Water Advocacy Team (WAT) will be crucial to understanding the impacts of waste disposal writ large.  It seems like the “food vs energy” nexus has come to a head in the heart of the U.S. Bread Basket. We’ll continue to highlight and map the issues associated with this topic in the coming months and years.

Data Download Links

The following links contain the data used in the above tables and map, for use in excel and with Geographic Information Systems (GIS).

[1] To learn more about Induced Seismicity, read an exclusive FracTracker two-part series from former researcher with Virginia Tech Department of Geosciences, Ariel Conn: Part I and Part II.

Additionally, the USGS has created an Induced Earthquakes landing page as part of their Earthquake Hazards Program.

Oklahoma and Kansas Class II Injection Wells and Earthquakes

By Ted Auch, Great Lakes Program Coordinator, FracTracker Alliance
In collaboration with Caleb Gallemore, Assistant Professor in International Affairs, Lafayette University

The September 3rd magnitude 5.8 earthquake in Pawnee, Oklahoma, is the most violent example of induced seismicity, or “man-made” earthquakes, in U.S. history, causing Oklahoma governor Mary Fallin to declare a state of emergency. This was followed by a magnitude 4.5 earthquake on November 1st prompting the Oklahoma Corporation Commission (OCC) and U.S. EPA to put restrictions on injection wells within a 10-mile radius of the Pawnee quake.

And then on Sunday, November 6th, a magnitude 5.0 earthquake shook central Oklahoma about a mile west of the Cushing Hub, the largest commercial crude oil storage center in North America capable of storing 54 million barrels of crude. This is the equivalent of 2.8 times the U.S. daily oil refinery capacity and 3.1 times the daily oil refinery capacity of all of North America. This massive hub in the North American oil landscape also happens to be the southern terminus of the controversial Keystone pipeline complex, which would transport 590,000 barrel per day over more than 2,000 miles (Fig. 1). Furthermore, this quake demonstrated the growing connectivity between Class II injection well associated induced seismicity and oil transport/storage in the heart of the US version of Saudi Arabia’s Ghawar Oil Fields. This increasing connectivity between O&G waste, production, and processing (i.e., Hydrocarbon Industrial Complex) will eventually impact the wallets of every American.

North American Oil Refinery Capacity, Pipelines, and Cushing, OK

Figure 1. The Keystone Pipeline would transport 590,000 bpd over more than 2,000 miles.

This latest earthquake caused Cushing schools to close. Magellan Midstream Partners, the major pipeline and storage facility operator in the region, also shut down in order to “check the integrity of our assets.” Compounding concerns about induced seismicity, the Cushing Hub is the primary price settlement point for West Texas Intermediate that, along with Brent Crude, determines the global price of crude oil and by association what Americans pay for fuel at the pump, at their homes, and in their businesses.

Given the significant increase in seismic activity across the U.S. Great Plains, along with the potential environmental, public health, and economic risks at stake, we thought it was time to compile an inventory of Class II injection well volumes. Because growing evidence points to the relationship between induced seismicity and oil and gas waste disposal, our initial analysis focuses on Oklahoma and Kansas. The maps and the associated data downloads in this article represent the first time Class II injection well volumes have been compiled in a searchable and interactive fashion for any state outside Ohio (where FracTracker has compiled class II volumes since 2010). Oklahoma and Kansas Class II injection well data are available to the public, albeit in disparate formats and diffuse locations. Our synthesis makes this data easier to navigate for concerned citizens, policy makers, and journalists.

Induced Seismicity Past, Present, and Future

inducedseismicity_figure

Figure 2. Central U.S. earthquakes 1973-August 15, 2015 according to the U.S. Geological Survey (Note: Based on our analysis this exponential increasing earthquakes has been accompanied by a 300 feet per quarter increase in the average depth of earthquakes across Oklahoma, Kansas, and Texas).

Oklahoma, along with Arkansas, Kansas, Ohio, and Texas, is at the top of the induced seismicity list, specifically with regard to quakes in excess of magnitude 4.0. However, as the USGS and Virginia Tech Seismological Observatory (VTSO)[1] have recently documented, an average of only 21 earthquakes of magnitude 3.0 or greater occurred in the Central/Eastern US between 1973 and 2008. This trend jumped to an average of 99 between 2009 and 2013. In 2014 there were a staggering 659 quakes. The exponential increase in induced seismic events can be seen in Figure 2 from a recent USGS publication titled “High-rate injection is associated with the increase in U.S. mid-continent seismicity,” where the authors note:

“An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection…We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells.”

hydraulic-fracturing-freshwater-demand

Figure 3. Average freshwater demand per hydraulically fractured well across four U.S. shale plays and the annual percent increase in each of those plays.

This trend suggests that induced seismicity is the new normal and will likely increase given that: 1) freshwater demand per hydraulically fractured well is rising all over the country, from 11-15% per year in the Marcellus and Bakken to 20-22% in the Denver and Midland formations, 2) the amount of produced brine wastewater parallels these increases almost 1-to-1, and 3) the unconventional oil and gas industry is using more and more water as they begin to explore the periphery of primary shale plays or in less productive secondary and tertiary plays (Fig. 3).

Oklahoma

The September, 2016, Pawnee County Earthquake

This first map focuses on the September, 2016 Pawnee, OK Magnitude 5.8 earthquake that many people believe was caused by injecting high volume hydraulic fracturing (HVHF) waste into class II injection wells in Oklahoma and Kansas. This map includes all Oklahoma and Kansas Class II injection wells as well as Oklahoma’s primary geologic faults and fractures.

Oklahoma and Kansas Class II injection wells and geologic faults

View map fullscreenHow FracTracker maps work

Pawnee, Oklahoma 5.8 magnitude earthquake, September, 2016 & Active Class II Injection Wells

Figure 4. The September, 2016 Pawnee, Oklahoma 5.8M earthquake, neighboring active Class II injection wells, underlying geologic faults and fractures.

Of note on this map is the geological connectivity across Oklahoma resulting from the state’s 129 faults and fractures. Also present are several high volume wells including Territory Resources LLC’s Oldham #5 (1.45 miles from the epicenter, injecting 257 million gallons between 2011 and 2014) and Doyle #5 wells (0.36 miles from the epicenter, injecting 61 million gallons between 2011 and 2015), Staghorn Energy LLC’s Hudgins #1 well (1.43 miles from the epicenter, injecting 11 million gallons between 2011 and 2015 into the Red Fork formation), and Cooke Co Production Co.’s Laird #3-35 well (1.41 miles from the epicenter, injecting 6.5 million gallons between 2011 and 2015). Figure 4 shows a closeup view of these wells relative to the location of the Pawnee quake.

Class II Salt Water Disposal (SWD) Injection Well Volumes

This second map includes annual volumes of disposed wastewater across 10,297 Class II injection wells in Oklahoma between 2011 and 2015 (Note: 2015 volumes also include monthly totals). Additionally, we have included Oklahoma’s geologic faults and fractures for context given the recent uptick in Oklahoma and Kansas’ induced seismicity activity.

Annual volumes of class II injection wells disposal in Oklahoma (2011-2015)

View map fullscreenHow FracTracker maps work | Download map data

Oklahoma statistics for 2011 to 2015 (Table 1):

  1. Maximum volume to date (for a single Class II injection well): 105,979,598 barrels, or 4,080,214,523 gallons (68,003,574 gallons per month), for the New Dominion, LLC “Chambers #1” well in Oklahoma County.
  2. Total Volume to Date: 10,655,395,179 barrels or 410,232,714,392 gallons (6,837,211,907 gallons per month).
  3. Mean volume to date across the 10,927 Class II injection wells: approximately 975,144 barrels per well or 37,543,044 gallons (625,717 gallons per month).
  4. This map also includes 632 Class II wells injecting waste into the Arbuckle Formation which is believed to be the primary geological formation responsible for the 5.0 magnitude last week in Cushing.

Kansas

Below is an inventory of monthly oil and gas waste volumes (barrels) disposed across 4,555 Class II injection wells in Kansas between 2011 and 2015. This map will be updated in the Spring of 2017 to include 2016 volumes. A preponderance of this data comes from 2015 with a scattering of volume reports across Kansas between 2011 and 2014.

Monthly Class II injection wells volumes in Kansas (2011-2015)

View map fullscreenHow FracTracker maps work | Download map data

Kansas statistics for 2015 (Table 1):

  1. Maximum volume to date (for a single Class II injection well): 9,016,471 barrels, or 347,134,134 gallons (28,927,845 gallons per month), for the Sinclair Prairie Oil Co. “H.J. Vohs #8” well in Rooks County. This is a well that was initially permitted and completed between 1949 and 1950.
  2. Total Volume to date: 1,060,123,330 barrels or 40,814,748,205 gallons (3,401,229,017 gallons per month).
  3. Mean volume to date across the 4,555 Class II injection wells: approximately 232,738 barrels per well or 8,960,413 gallons (746,701 gallons per month).

Table 1. Summary of Class II SWD Injection Well Volumes across Kansas and Oklahoma

 

 

Sum Average Maximum
No. of Class II
SWD Wells
Barrels Sum To Date Per Year Sum To Date Per Year
Kansas* 4,555 1.06 BB 232,738 9.02 MB
Oklahoma** 10,927 10.66 BB 975,143 195,029 105.98 MB 21.20 MB

* Wells in the counties of Barton (279 wells), Ellis (397 wells), Rooks (220 wells), Russell (199 wells), and Ness (187 wells) account for 29% of Kansas’ active Class II wells.

** Wells in the counties of Carter (1,792 wells), Creek (946 wells), Pontotoc (684 wells), Seminole (476 wells), and Stephens (1,302 wells) account for 48% of Oklahoma’s active Class II wells.

Conclusion

If the U.S. EPA’s Underground Injection Control (UIC) estimates are to be believed, the above Class II volumes account for 19.3% of the “over 2 billion gallons of brine…injected in the United States every day,” and if the connectivity between injection well associated induced seismicity and oil transport/storage continues to grow, this issue will likely impact the lives of every American.

Given how critical the Cushing Hub is to US energy security and price stability one could easily argue that a major accident there could result in a sudden disruption to fuel supplies and an exponential increase in “prices at the pump” that would make the 240% late 1970s Energy Crisis spike look like a mere blip on the radar. The days of $4.15 per gallon prices the country experienced in the summer of 2008 would again become a reality.

In sum, the risks posed by Class II injection wells and are not just a problem for insurance companies and residents of rural Oklahomans and Kansans, induced seismic activity is a potential threat to our nation’s security and economy.

Downloads

FracTracker Induced Seismicity Infographic (print quality)

Oklahoma Class II SWD Injection Well Annual Volumes 2011 to 2015 (Barrels)

Kansas Class II SWD Injection Well Monthly Volumes 2011 to 2015 (Barrels)

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.

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.