Oklahoma now has more earthquakes on a regular basis than California.  Are they due to fracking?

In a few cases, yes, but in most cases no.  Only a few of the over 2000 magnitude 3 and larger earthquakes since 2009 that have occurred in Oklahoma have been connected to hydraulic fracturing. The majority of earthquakes in Oklahoma are caused by the industrial practice​ known as "wastewater disposal". Wastewater disposal is a ​separate ​process in which fluid waste from oil and gas production is injected deep underground far below ground water or drinking water aquifers. In Oklahoma over 90% of the wastewater that is injected is a byproduct of oil extraction process and not waste frack fluid.

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What work is the USGS doing to better understand the occurrence of injection-induced earthquakes?

USGS supports both internal and external (university-based) research on the causes of induced earthquakes. This research focuses on injection-induced earthquakes, including from wastewater disposal, enhanced geothermal technologies, and at carbon dioxide sequestration sites. USGS and its university partners have also deployed seismometers at sites...

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 the September 23, 2016 earthquake in central Oklahoma. It had a magnitude of 5.8. 4 M5+ earthquakes have occurred in Oklahoma, 3 of which occurred in 2016. In 2011 a magnitude 5.3 earthquake was induced by fluid injection in the Raton Basin...

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 commonly occur several kilometers below the injection point.

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 conclusive example linking injection operations to triggering of major earthquakes; However, we cannot eliminate this possibility.

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

To produce natural 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 causes extremely small earthquakes, but they are...

How does the injection of wastewater at depth cause earthquakes?

Earth's crust is pervasively fractured at depth by faults. These faults can sustain high stresses without slipping because natural "tectonic" stress and the weight of the overlying rock pushes the opposing fault blocks together, increasing the frictional resistance to fault slip. The injected wastewater counteracts the frictional forces on faults...

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. Three conditions must be met for injection to induce an earthquake: 1) presence of a fault; 2) stresses acting on the fault favorable to slip and 3) a pathway for the pressure increase from injection to interact with the fault. Evidence from some case histories suggests that the magnitude of...

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 on wastewater disposal wells and the EPA's Underground Injection...
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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 7, 2016

Magnitudes for Oklahoma Earthquakes Shift Upward

Revisions follow standard USGS re-analysis

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.

Date published: February 13, 2016

Magnitude 5.1 Earthquake in Oklahoma

A magnitude 5.1 earthquake struck in Oklahoma on February 13, 2016 at 11:07:06 am local time.

Date published: October 26, 2015

A Century of Induced Earthquakes in Oklahoma?

The rate of earthquakes has increased sharply since 2009 in the central and eastern United States, with growing evidence confirming that these earthquakes are primarily caused by human activity, namely the injection of wastewater in deep disposal wells.

Attribution: Natural Hazards
Date published: March 6, 2014

2011 Oklahoma Induced Earthquake May Have Triggered Larger Quake

 In a new study involving researchers at the U.S. Geological Survey, scientists observed that a human-induced magnitude 5.0 earthquake near Prague, Oklahoma in November 2011 may have triggered the larger M5.7 earthquake less than a day later. 

Attribution: Earthquake Hazards
Date published: October 22, 2013

Earthquake Swarm Continues in Central Oklahoma

Since January 2009, more than 200 magnitude 3.0 or greater earthquakes have rattled Central Oklahoma, marking a significant rise in the frequency of these seismic events.  

Filter Total Items: 12
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
...
USGS map displaying potential to experience damage from a natural or human-induced earthquake in 2017
February 24, 2017

USGS Forecast for Damage from Natural and Induced Earthquakes in 2017

USGS map displaying potential to experience damage from a natural or human-induced earthquake in 2017. Chances range from less than one percent to 12 percent.

USGS map showing the location of earthquakes greater than or equal to magnitude 4.0 in Oklahoma and the Raton Basin in 2016
February 24, 2017

Potentially Damaging 2016 Earthquakes in Oklahoma and the Raton Basin

USGS map showing the location of earthquakes greater than or equal to magnitude 4.0 in Oklahoma and the Raton Basin in 2016.

Damage to buildings in Cushing, Oklahoma from the magnitude 5.0 earthquake on November 6, 2016
February 24, 2017

Damage in Cushing, Oklahoma from the Magnitude 5.0 Earthquake in 2016

Damage to buildings in Cushing, Oklahoma from the magnitude 5.0 earthquake on November 6, 2016. Unreinforced brick and stone masonry buildings and facades are vulnerable to strong shaking. Photograph credit: Dolan Paris, USGS

Damage to buildings in Cushing, Oklahoma from the magnitude 5.0 earthquake in 2016
February 24, 2017

Damage in Cushing, Oklahoma from the Magnitude 5.0 Earthquake in 2016

Damage to buildings in Cushing, Oklahoma from the magnitude 5.0 earthquake on November 6, 2016. Unreinforced brick and stone masonry buildings and facades are vulnerable to strong shaking. Photograph credit: Dolan Paris, USGS

House damage in central Oklahoma from a magnitude 5.6 earthquake in 2011
February 23, 2017

Damage in central Oklahoma from a magnitude 5.6 earthquake in 2011

House damage in central Oklahoma from the magnitude 5.6 earthquake on Nov. 6, 2011. Research conducted by USGS geophysicist Elizabeth Cochran and her university-based colleagues suggests that this earthquake was induced by injection into deep disposal wells in the Wilzetta North field. Credit: Brian Sherrod, USGS

Population Exposed to Potentially Damaging Earthquake Groundshaking
October 11, 2016

Population Exposed to Potentially Damaging Earthquake Groundshaking

USGS map showing (1) the locations of major populations and (2) the intensity of potential earthquake ground shaking that has a 2% chance of occurring in 50 years.

Map showing 21 areas of observed rapid changes in seismicity related to wasterwater injection.
April 15, 2016

Wastewater observed seismicity map (2016)

USGS map displaying 21 areas where scientists have observed rapid changes in seismicity that have been associated with wastewater injection. The map also shows earthquakes—both natural and induced—recorded from 1980 to 2015 in the central and eastern U.S. with a magnitude greater than or equal to 2.5.

Oklahoma windmill at sunset
July 30, 2014

Oklahoma windmill at sunset

Oklahoma windmill at sunset

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

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