Why did Oklahoma earthquakes increase, and can they damage houses?

Reviewed by Preston, Oklahoma foundation repair consultant · Updated 2026-10-14

In short: Oklahoma's earthquake activity rose sharply after 2009, and the state geological survey links that increase mainly to deep disposal of oil-and-gas wastewater. The largest recorded event was the 2016 Pawnee earthquake. Moderate quakes can crack plaster and masonry, and earthquake damage and soil movement can look alike.

What happened to Oklahoma's earthquake activity?

The Oklahoma Geological Survey (OGS) states that a large area of the state has had greatly increased seismic activity since 2009, and especially since 2013 ¹. The OGS describes these earthquakes as induced primarily by deep injection of produced water from oil and gas operations ¹. "Produced water" is the salty water that comes out of wells along with oil and gas and is pumped back underground for disposal. "Induced" means caused by human activity rather than natural processes alone.

Wastewater disposal, not fracking itself

The USGS states that disposal of waste fluids produced with oil is the primary cause of the rise in central U.S. earthquakes, and that only 1 to 2 percent of Oklahoma earthquakes can be linked to hydraulic fracturing ("fracking") ⁸. Less than 10 percent of the water injected into Oklahoma disposal wells is spent fracking fluid; most is salty water produced along with oil ⁸.

Much of that water went into the Arbuckle, a deep rock formation under most of Oklahoma that readily absorbs fluid ⁹. Researchers identified injection into the granite basement rock below it as a major risk factor for triggering earthquakes ⁹.

How regulators responded

The OGS noted in 2016 that actions by the Oklahoma Corporation Commission, the state agency that regulates oil and gas wells, and changes in the oil market may already have affected seismic activity ¹. Key steps included:

• March 2015: The Commission directed operators of 347 Arbuckle disposal wells in quake-prone areas to prove their wells did not reach basement rock, to plug back wells that did, or face a 50 percent volume cut ⁹.
• March 2016: A plan covering more than 5,200 square miles of central Oklahoma aimed to cut disposal volumes 40 percent below 2014 totals; together with a northwestern plan it covered more than 640 disposal wells ¹⁰.

The rise and decline in numbers

The OGS detected 2,972 earthquakes of all sizes in 2022, down from 5,150 in 2021 ¹². Smaller quakes continue, so a felt earthquake today is still possible.

What are the largest recorded Oklahoma earthquakes?

Source: OGS top-ten list ². Four of the state's ten largest listed events occurred in 2016 ².

Pawnee, 2016

The OGS fact sheet issued after the Pawnee quake listed a preliminary magnitude of 5.6, centered 9.3 miles northwest of Pawnee at a depth of about 3.5 miles, on a strike-slip fault (one where the ground slides sideways) ³. The later top-ten list gives 5.8 ². The fact sheet notes that central U.S. earthquakes are felt over an area more than ten times larger than similar West Coast quakes ³.

Cushing, 2016

The magnitude 5.0 Cushing earthquake in November 2016 began only about 4 km (2.5 miles) deep, and nearby instruments recorded peak horizontal ground accelerations of 0.44 g to 0.58 g ¹⁵. Century-old unreinforced brick buildings downtown were heavily damaged and some were demolished ¹⁵.

Fairview aftershocks

The magnitude 5.1 Fairview earthquake in February 2016 was followed by aftershocks; by July 2016, eight aftershocks of magnitude 4 or larger had occurred on the same fault zone in Woods County ⁴. The OGS noted that aftershock sequences tend to last longer in the middle of the continent than along plate boundaries ⁴.

How do magnitude and intensity differ?

• Magnitude measures the energy released at the source. One number per earthquake.
• Intensity, on the Modified Mercalli Intensity (MMI) scale, describes shaking effects at a particular place. It varies with distance and ground conditions.

The OGS describes MMI VI as minor damage such as falling plaster and a few cracks ¹. The chance of MMI VII damage, comparable to the 2011 Prague earthquake, was described as very small and limited to a much smaller area ¹. The OGS also noted the 2016 USGS hazard model did not address cumulative damage from many small earthquakes over time ¹.

Where can the earthquake record be checked?

• OGS earthquake catalogs: yearly lists of Oklahoma events. The OGS describes them as fairly complete for magnitude 2.9 and larger since 1980 ⁵.
• Report a felt quake: the OGS asks residents to report felt earthquakes on the USGS Did You Feel It? site and on its own form ⁶.
• USGS Did You Feel It?: collects reports from people who felt a quake and turns them into maps of shaking and damage ⁷.
• USGS ShakeMap: maps of the ground shaking recorded at seismic stations soon after an earthquake, including an estimated Modified Mercalli Intensity map showing where shaking was likely felt and where damage may have occurred; accuracy is highest near stations ¹³.

Why do earthquakes matter for foundations?

In the moderate Oklahoma quakes, damage concentrated in masonry. After the Pawnee earthquake, emergency managers reported no building collapses and said much of the damage was to older brick and mortar buildings from the early 1900s; stones fell from the facade of a 1902 sandstone bank building ¹⁴. In Cushing, the worst damage was to century-old unreinforced brick buildings ¹⁵.

Earthquakes and expansive clay can both crack walls and slabs, and the patterns differ; see earthquake shaking damage for how shaking damage typically appears. A step-by-step comparison of timing, crack edges and elevation data is on the seismic damage vs soil movement page. The deep geology behind these events is summarized in Oklahoma geologic provinces.

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