Does fracking cause earthquakes?

Most induced earthquakes are not directly caused by hydraulic fracturing (fracking). 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.

Wastewater disposal wells typically operate for longer durations and inject much more fluid than is injected during the hydraulic fracturing process, making them more likely to induce earthquakes. In Oklahoma, which has the most induced earthquakes in the United States, 2% of earthquakes can be linked to hydraulic fracturing operations. Given the high rate of seismicity in Oklahoma, this means that there are still many earthquakes induced by hydraulic fracturing. The remaining earthquakes are induced by wastewater disposal. The largest earthquake known to be induced by hydraulic fracturing in the United States was a magnitude 4.0 earthquake that occurred in 2018 in Texas.

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Oklahoma has had a surge of earthquakes since 2009. Are they due to fracking?

Beginning in 2009, Oklahoma experienced a surge in seismicity. This surge was so large that its rate of magnitude 3 and larger earthquakes exceeded California’s from 2014 through 2017. bar graph Bar graph showing the...

How large are the earthquakes induced by fluid injection?

The largest earthquake induced by fluid injection that has been documented in the scientific literature was a magnitude 5.8 earthquake on September 23, 2016 in central Oklahoma. Four magnitude 5+ earthquakes have occurred in Oklahoma, three of which occurred in 2016. In 2011, a magnitude 5.3 earthquake was induced by fluid injection in the Raton...

Are earthquakes induced by fluid-injection activities always located close to the point of injection?

No. Given enough time, the pressure increase created by injection can migrate substantial horizontal and vertical distances from the injection location. Induced earthquakes can occur 10 or more miles from injection wells. Induced earthquakes can also occur a few miles below injection wells. Learn more: USGS Induced Earthquakes

Is there any possibility that a wastewater injection activity could interact with a nearby fault to trigger a major earthquake that causes extensive damage over a broad region?

So far, there is no documented example linking injection operations to triggering of major earthquakes. However, we cannot eliminate this possibility. Other human activities--for example oil production in Uzbekistan--have induced M7+ earthquakes. Learn more: USGS Induced Earthquakes

Does the production of oil and gas from shales cause earthquakes? If so, how are the earthquakes related to these operations?

To produce oil and gas from shale formations, it is necessary to increase the interconnectedness of the pore space (permeability) of the shale so that the gas can flow through the rock mass and be extracted through production wells. This is usually done by hydraulic fracturing ("fracking"). Fracking intentionally causes small earthquakes (...

How does the injection of fluid at depth cause earthquakes?

The fluid that is injected at depth is sometimes hydraulically connected to faults. When this happens, fluid pressures increase within the fault, counteracting the frictional forces on faults. This makes earthquakes more likely to occur on them. An analog to this system is an air hockey table. When an air hockey table is off, the puck does not...

Is it possible to anticipate whether a planned wastewater disposal activity will trigger earthquakes that are large enough to be of concern?

Currently, there are no methods available to do this in a definitive sense. We have developed methods that use injection information to help us determine whether injection activities might cause induced earthquakes and rule out other injection activities that are unlikely to induce earthquakes, but we cannot say either with certainty. There are a...

Do all wastewater disposal wells induce earthquakes?

No. Of more than 150,000 Class II injection wells in the United States, roughly 40,000 are waste fluid disposal wells for oil and gas operations. Only a small fraction of these disposal wells have induced earthquakes that are large enough to be of concern to the public. Learn more: USGS Induced Earthquakes EPA's Underground Injection Control (UIC...
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Date published: October 24, 2016

Wastewater Disposal Likely Induced February 2016 Magnitude 5.1 Oklahoma Earthquake

Distant wastewater disposal wells likely induced the third largest earthquake in recent Oklahoma record, the Feb. 13, 2016, magnitude 5.1 event roughly 32 kilometers northwest of Fairview, Oklahoma. These findings from the U.S. Geological Survey are available in the online edition of Geophysical Research Letters.

Date published: September 3, 2016

Magnitude 5.8 Earthquake in Oklahoma

A magnitude 5.8 earthquake struck in Oklahoma on September 3, 2016 at 12:02:44 UTC (7:02 am local time). 

Date published: March 28, 2016

EarthWord – Induced Seismicity

The occurrence or frequency of earthquakes for which the origin is attributable to human activities.

Date published: March 28, 2016

Induced Earthquakes Raise Chances of Damaging Shaking in 2016

For the first time, new USGS maps identify the potential for ground shaking from both human-induced and natural earthquakes in 2016.

Filter Total Items: 6
May 31, 2018

PubTalk 5/2018 — Yes Humans really are causing induced earthquakes

Title: Yes, Humans Really Are Causing Earthquakes! How Energy Industry Practices are Causing Earthquakes in America's Heartland

  • In every year since 2014, Oklahoma has had more earthquakes than California.
  • Oil and gas operations are "inducing" these earthquakes.
  • The earthquake rate has dropped by more than 50 percent due to changes in industry
video thumbnail: Science or Soundbite? Shale Gas, Hydraulic Fracturing, and Induced Earthquakes
April 3, 2012

Science or Soundbite? Shale Gas, Hydraulic Fracturing, and Induced Earthquakes

Hydraulic fracturing is the process of injecting wells with water, sand, and chemicals at very high pressure. This process creates fractures in deeply buried rocks to allow for the extraction of oil and natural gas as well as geothermal energy. USGS scientists discuss the opportunities and impact associated with hydraulic fracturing. Doug Duncan, associate coordinator for

Attribution: Natural Hazards
Oil production and wastewater disposal

Wastewater injection

Most wastewater currently disposed of across the nation is generated and produced in the process of oil and gas extraction. Saltwater is produced as a byproduct during the extraction process. This wastewater is found at nearly every oil and gas extraction well.

The other main constituent of wastewater is leftover hydraulic fracturing fluid. Once hydraulic fracturing

Generalized image showing the key points in hydraulic fracturing

Generalized image showing the key points in hydraulic fracturing

Generalized image showing the key points in hydraulic fracturing for oil and gas development where water is part of the process.

Attribution: Energy and Minerals
two maps os the U.S.

2018 Induced Seismicity Hazard

Map showing the 1‐year chance of minor (top) and moderate (bottom) damaging earthquake shaking in the United States in 2018. Hazard from the western United States from the 2014 National Seismic Hazard Maps (Petersen et al., 2014) is shown on the left of both maps for comparison.

March 28, 2018

USGS Forecast for Damage from Natural and Induced Earthquakes in 2018

USGS map displaying potential to experience damage from natural or human-induced earthquakes in 2018. Chances range from less than 1 percent to 14 percent.