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CUSHING, Okla. – In recent years, earthquakes have become a common occurrence for many residents across Oklahoma.

20 years ago, experts say earthquakes in the Sooner State were few and far between.

Now, it is common for the Oklahoma Geological Survey and the U.S. Geological Survey to record at least one small quake a day across the state.

For months, many residents and business owners have been wondering what is behind the increased activity.

Earlier this year, the U.S. Geological Survey announced that it believed disposal wells used by oil companies was to blame.

Now, the Oklahoma agency says it agrees.

“Based on observed seismicity rates and geographical patterns of migrating seismicity in Oklahoma, which follow major oil and gas plays with large amounts of produced water, these rates and patterns of seismicity are very unlikely to represent a naturally occurring rate change and process,” a statement from OGS said.

The Oklahoma Geological Survey says the rate of earthquakes that top a 3.0 magnitude have increased dramatically since 2008.

In 2008, the OGS says Oklahoma was experiencing one and a half earthquakes of that magnitude a year.

The OGS says the current average rate of 3.0 magnitude earthquakes is two and a half per day, which is 600 times the historical level.

“The Oklahoma Geological Survey considers it very likely that the majority of recent earthquakes, particularly those in central and north-central Oklahoma, are triggered by the injection of produced water in disposal wells,” the statement reads.

Experts say produced water is mixed with oil and gas under the Earth’s surface.

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When oil and gas is extracted, so is the water.

“It may come up with lead. It may come up with arsenic. It may come up with trace amounts of things you certainly don’t want sitting on the ground somewhere,” said Matt Skinner, with the Oklahoma Corporation Commission.

The water is then separated from the oil and gas and re-injected into disposal wells.

“The observed seismicity of greatest concentration, namely in central and north-central Oklahoma, can be observed to follow the oil and gas activities (plays) characterized by large amounts of produced water. Seismicity rates are observed to increase after a time delay as injection volumes increase within these plays. In central and north-central Oklahoma, this time delay has typically been several weeks to a year or more.”

Skinner says pumping the toxic liquid back into the ground is still the best option, at least for now.

“There are other ways but they carry with them their own environmental problems,” said Skinner.

Another option for disposal that is used in other states are pits, which hold the water above ground so it can evaporate.

However, Skinner says it is still not a great option because of the amount of contamination in the water.

The Oklahoma Oil & Gas Association says additional research is needed to determine how disposal wells can be operated without causing earthquakes.

“There may be a link between earthquakes and disposal wells, but we – industry, regulators, lawmakers or state residents – still don’t know enough about how wastewater injection impacts Oklahoma’s underground faults,” said Chad Warmington, the association’s president.

After OGS released its findings, Rep. Cory Williams called for a moratorium on oil and gas wastewater disposal wells in 16 counties that have been identified as “areas of interest.”

The highest frequency of earthquakes occur in Alfalfa, Garfield, Noble, Payne, Lincoln, Oklahoma, Grant and Logan counties.

The Corporation Commission, which regulates the oil and gas industry, Gov. Mary Fallin and major oil producers in Oklahoma “have consistently said they would re-evaluate this issue if scientific evidence demonstrated that there was a connection between disposal wells and earthquakes,” said Williams. “Well, the science on induced seismicity is in. It’s time to take swift action to protect the lives and property of this state’s citizens.”

However, Warmington says that is just not feasible.

“Not only would that halt oil and natural gas production in Oklahoma, there is no scientific evidence that stopping wastewater injection would result in fewer earthquakes. That is why we need a better understanding of what is causing our earthquakes.”

The Corporation Commission has also made a request that wells in certain areas not drill past a certain depth. They are also putting limits on how close a well can be to a known fault line.

“I get woken up all the time. My home is cracking. I have damage to my home. I know what it’s like to go through that,” Skinner said.

WATCH: Energy reporter for the Journal-Record newspaper Sarah Terry-Cobo dropped by the set to talk about the growing concern over fracking and earthquakes here in Oklahoma. Watch her interview below

Read Sarah Terry-Cobo’s article in the Journal Record here.

Get more info about earthquakes in our state here.

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