For decades, we’ve known that the injection of fluids in the subsurface of the Earth has the potential to cause earthquakes- and since this is what occurs in hydraulic fracturing (fracking), it makes sense that fracking earthquakes can occur.
Here’s what you should know about how fracking causes earthquakes and the locations most at risk.
1. What is fracking?
Fracking, also called hydraulic fracturing, is the process of injecting liquids, chemicals, or sand at high pressure into subterranean rocks, boreholes, etc.
This injection forces open existing fissures and allows the extraction of oil or gas.
2. Does hydraulic fracking cause earthquakes?
Yes, although most induced earthquakes are not caused by fracking.
As the U.S. Geological Survey states, “The recent increase in earthquakes in the central United States is primarily caused by disposal of waste fluids that are a byproduct of oil production.”
3. How widespread, frequent, and large are hydraulic fracturing induce earthquakes?
Less than 1 percent of fracking wells cause induced earthquakes.
Research shows that this low percentage is because all the geological conditions must align in the same place: tectonic, geomechanical, and hydrological for an earthquake to occur.
So, pressurized fracking fluids may prompt an earthquake only if it connects with a susceptible fault.
Still, the total number of earthquakes produced by fracking can still be relatively high.
For example, in Oklahoma, approximately 2% of all earthquakes can be linked to fracking.
These fracking earthquakes occur most frequently during the hydraulic stimulation process (or when water is pumped into the well).
With that, earthquakes can still occur after hydraulic fracturing has been completed.
The largest earthquake prompted by hydraulic fracking occurred in the Sichuan Basin of China on December 16, 2018.
It was a 5.7 magnitude.
4. What are the main physical characteristics of hydraulic fracturing-induced earthquakes?
The physical characteristics of fracking earthquakes are no different than “natural” earthquakes.
In terms of fluid flow, the same characteristics are associated with both types.
These include swarm-like sequences, temporal correlation with the injection source, spatial proximity to the fluid source, and a linear relationship between injected volume and the number of induced earthquakes.
Fracking earthquakes offer opportunities to understand natural earthquakes related to fluid flow due to their similarities.
5. Is fracking bad for the earth?
It’s no secret that obtaining fossil fuels through any process is bad for the planet.
The process of extracting these fuels also risks causing pollution and harming public health.
So, in short, yes.
Fracking can be bad for the planet, and here’s an in-depth look at why.
Climate change
Climate change is already a big issue.
Changes in the weather and climate patterns have started to put lives at risk.
Extreme temperatures on both ends of the spectrum can become deadly, and when ocean temperatures rise, hurricanes get stronger and stronger.
To help prevent climate change, energy experts have said that much of the gas that’s been discovered by energy companies must stay in the ground.
If this gas were to be extracted by fracking, then we may not be able to meet our emission reduction targets.
Sticking to these targets is essential in limiting the effects of climate change.
On top of that, fracked gas appears to leak methane into the atmosphere, and since this gas is a greenhouse gas, it makes an impact.
Having said this, natural gas emits fewer greenhouse gases when burned than other fossil fuels, so gas-powered plants can reduce overall emissions when they replace coal-powered plants.
At the same time, natural gas still releases carbon dioxide when burned, and if natural gas outcompetes or replaces renewable energy alternatives, it can stimy efforts to reduce global emissions.
Pollution and health risks
Fracking can cause air, water, and noise pollution when the chemicals used in the process leak.
The process is exempt under the Safe Drinking Water Act, which means that the EPA does not regulate fracking fluids, even if chemicals potentially spill into nearby water supplies or cause pollution above ground.
The U.S. has had this happen several times.
If you’re curious about what chemicals are used in fracking water, see below.
| Chemicals Used in Fracking | Daily Use |
| Citric Acid | Lemon |
| Hydrochloric Acid | Swimming pools |
| Glutaraldehyde | Disinfectant |
| Guar | Ice cream |
| Dimethylformamide | Plastics |
| Isopropanol | Deodorant |
| Borate | Hand soap |
| Ammonium Persulphate | Hair dye |
| Potassium Chloride | IV fluids |
| Sodium Carbonate | Detergent |
| Ethylene Glycol | De-icer |
| Ammonium Bisulphate | Cosmetics |
| Petroleum Distillate | Cosmetics |
Land
Large-scale fracking can greatly impact the land in a country.
Fracking is an industrial operation that requires huge quantities of water and large numbers of trucks to deliver chemicals and remove contaminated wastewater.
In these cases, protected habitats and species could be affected in addition to any communities or neighbors living nearby.
6. What are the health hazards of fracking?
Fracking chemicals that leak into drinking water can cause the following health issues.
Headaches
Asthma symptoms
Childhood leukemia
Cardiac problems
Birth defects
Cancer
7. What was the largest earthquake induced by fracking?
The largest documented “fracking earthquake” was a magnitude of 4 in 2018.
It occurred in Texas.
8. Are earthquakes induced by fluid-injection activities always located close to the point of injection?
No, the pressure increase that the fluid injection creates can migrate substantial horizontal and vertical distances from its initial location.
Earthquakes associated with injection wells (but not necessarily fracking) can occur 10 or more miles from injection wells.
These earthquakes can also occur a few miles below injection wells.
9. Does the production of oil and gas from shales cause earthquakes?
Fracking is used when producing oil and gas from shale formations.
To extract gas and oil in this way, you must increase the interconnectedness of the pore space (also known as permeability) of the shale so that gas can flow through the rock mass and get extracted through production wells.
Fracking will intentionally cause small earthquakes (magnitude smaller than 1) to enhance permeability.
However, this process has also been linked to larger earthquakes such as an M4 earthquake in Texas.
Additionally, fracking fluids and saltwater trapped in the same formation as gas are returned to the surface.
Once at the surface, the wastewater will be disposed of by being injected into deep wells.
This injection of wastewater can cause earthquakes that are large enough to be damaging.
Although this wastewater disposal is a separate process, it is a byproduct of fracking, and it still has the ability to produce earthquakes.
10. What are the alternatives to fracking?
Rather than fracking, the government and energy companies should be investing in renewable energy.
This can not only reduce current emissions, but it can help tackle climate change in the future.
Plus, one big bonus is that there’s no risk of fracking earthquakes or any related damages.
If you’re considering building a house in the near future, upgrade your home with energy efficiency improvements.
By investing in things like insulation, double glazing, and heat pumps, you can help reduce the amount of gas needed.
You’ll cut your energy bills and reduce emissions.
11. Where is most at risk for fracking earthquakes?
Based on research conducted by the USGS, the states home to the most seismic activity linked to fracking-related injection wells are Arkansas, Colorado, Ohio, Kansas, Oklahoma, and Texas.
As mentioned earlier, in Oklahoma, for example, 2 percent of earthquakes can be linked to hydraulic fracturing operations.
This is twice the risk of fracking earthquakes that other locations see.
12. What can be done to mitigate the risk of fracking-induced earthquakes?
Scientists and the government can work together to help mitigate fracking earthquakes.
The key to successful regulation and mitigation is transparency between parties.
Scientists must build a relationship of trust between the government and those in the gas/oil industry.
One way to do this is by sharing accurate seismological data.
This data can be used to create comprehensive catalogs of earthquakes.
By cataloging the earthquakes, these parties can begin to conduct additional research and work together to prevent fracking in areas particularly at risk for earthquakes.
13. What are the facts about fracking earthquakes?
Fracking can be a hot topic.
Here are the facts about fracking earthquakes from USGS (U.S. Geological Survey).
Fracking is not directly causing most of the induced earthquakes
Wastewater disposal wells are more likely to induce earthquakes than fracking itself.
This is because the disposal wells often operate for longer durations and inject more fluid.
That said, because fracking produces wastewater, it’s impossible to separate one from the other.
Not all wastewater injection wells induce earthquakes
As noted above, many factors are required in order for an injection to prompt a felt earthquake.
Thus, most injection wells aren’t associated with them.
Here are the factors that can contribute to the triggering of earthquakes:
- The injection rate
- The total volume injected
- The presence of faults that are large enough to produce felt earthquakes
- Stress that is large enough to produce earthquakes
- The presence of pathways for the fluid pressure to travel from the injection point to faults
Wastewater is produced at all oil wells (not just hydraulic fracturing sites)
Most wastewater that’s disposed of nationwide is generated and produced in the process of oil and gas extraction.
Saltwater is a common byproduct during the extraction process, and it’s found at almost every oil and gas extraction well.
Another common fluid found at sites is leftover fracking fluid.
Drilling engineers will extract all fluids that remain in the well.
Some of the fluid can be repurposed in future fracking operations while the rest is disposed of in deep wells.
The content of the wastewater injected in disposal wells is highly variable
Although wastewater can cause an induced earthquake, in most cases, it has little or nothing to do with fracking.
For example, in Oklahoma, less than 10 percent of the water injected in wastewater disposal wells is used fracking fluid.
Most of the wastewater is actually saltwater that comes up along with the oil during the extraction process.
On the other hand, the fluid disposed of near earthquake sequences that occurred in Guy, Arkansas, and Youngstown, Ohio consisted largely of used fracking fluid.
So, it really depends on the site and what occurs there.
Induced seismicity can occur at significant distances from injection wells as well as various depths
A fracking earthquake doesn’t always occur at the site of injection.
It can be induced up to 10 miles (or more) away from the injection point.
Additionally, the depth at which the earthquake will occur can also vary.
Wells not requiring surface pressure to inject wastewater can still induce earthquakes
Even if you can pour fluid down a well without added pressure at the wellhead, you can still increase the fluid pressure within the formation.
This can induce an earthquake.
Final Thoughts
In short, fracking earthquakes absolutely exist.
The process of extracting oil and gas through fracking does cause them; however, most induced earthquakes today are not caused by fracking but rather by the disposal of waste fluids that are a byproduct of oil production.
Still, the U.S. has a long way to go when it comes to effectively protecting our climate and ensuring we lower carbon emissions.
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Disclaimer: we are not lawyers, accountants, or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.
Prior to starting Gokce Capital, Erika received a Bachelor of Architecture from the University of Southern California and a graduate degree in Urban Policy from Columbia University. She worked as both an architectural designer and engineer in New York before joining the New York City Department of Housing Preservation and Development.
Erika currently lives in the New York Metropolitan area with her spouse, daughter and cat. She is originally from Chicago and still considers herself a midwesterner at heart.
Erika also loves to read, write and travel (fun fact, she has visited all 50 states and more than 30 countries!). Her new book, Land Investing Mistakes: 11 True Stories You Need To Know Before Buying Land, is now available on Amazon.