Oklahoma Geological Survey warns more high-magnitude earthquakes possible

Bradon Long | Reporter

As earthquakes continue to rattle Oklahoma, researchers warn more severe quakes could be possible with continued drilling activities.

Oklahoma has seen an unprecedented increase in the number of earthquakes, at 600 times the average background rate, according to the Oklahoma Geological Survey.

Preliminary Fault Map

Preliminary Fault Map

Oklahoma State Seismologist Austin Holland noted that the earthquake risk presents itself not just in areas that have been hit in the last few years, but statewide as well.

“Earthquakes may occur anywhere in Oklahoma. To date, there has been at least one documented earthquake of 3.0 or higher in 74 of Oklahoma’s 77 counties, and because we cannot predict when or where a damaging earthquake may occur, it is important to be prepared,” Holland said.

The cause of the rise in earthquakes continues to spark scientific and legislative debate, with Oklahoma legislature hesitant to blame the oil and gas industry, which provides a large majority of the cash flow for the Oklahoma state economy.

However, scientific evidence gathered by the Oklahoma Geological Survey suggests the state legislature and oil and natural gas companies may have to accept their role in the increase of earthquakes across the state.

“To give you a natural reason [for the rise in earthquakes] would be extremely difficult,” Jennifer Morris, Associate Researcher at the Oklahoma Geological Survey said.

Many not accustomed to the oil and gas industry believe hydraulic fracking of the ground in oil wells is the cause of the rise in earthquakes.

This is not true, according to the OGS.

Wastewater disposal, a process in which water is separated from gathered oil and natural gas and injected back into the earth, is a process different than fracking, is seemingly the overarching cause of increased seismic activity.


“Hydraulic fracturing fluid is only up to maybe 10 percent of wastewater disposal, so this is more than just a fracking issue,” Morris said.

Nevertheless, fracking and wastewater disposal wells go hand in hand. According to Morris, one cannot occur without the other.

“There is no current natural way to separate the fracking and wastewater disposal processes,” Morris said.

A growing concern for many Oklahomans is not just the increase in the number of quakes, but also the potential for the increase in magnitude.

“I have been in Oklahoma for over 40 years, but I didn’t feel an earthquake until 2011,” Northwest Oklahoma resident Tara Long said.

Long, a native rural Oklahoman, is no stranger to the oil and gas industry. However, despite the industry being a leading monetary concern for her area, she echoes the opinions of several of her fellow Oklahomans.

“A large concern of mine in more earthquakes is how large are they going to get? We can’t really defend ourselves easily against earthquakes,” Long said. Their money is not worth endangering my life in my mind.”

Looking at the numbers, the number of earthquakes magnitude 3.0 or greater per year increased by nearly 2,000 percent in 2009 compared to the three decade average of previous years.

Furthermore, the number of earthquakes in the same category increased from 109 in 2013 to nearly 600 in 2014.

Perhaps most disturbingly, the number of magnitude 4.0 earthquakes or greater, over ten times stronger than a 3.0, increased by over 300 percent in 2014.

OGS officials share Long’s concern.

For every ten magnitude-3 earthquakes, researchers usually see one magnitude-4.

For every ten magnitude-4 earthquakes, researchers will usually see one magnitude-5.

“So, as our magnitude 4.0 earthquakes increase, there is a legitimate concern for larger earthquakes to happen,” Morris said.

The largest earthquake in Oklahoma history took place on November 6, 2011, near Prague, Oklahoma. The 5.6 magnitude earthquake could be felt all the way into Colorado, causing damage to homes in Central Oklahoma. According to the OGS, the state is due for another quake of that magnitude in the near future.

With the number of earthquakes at almost 500 already at this point in 2015 and hydraulic fracking and wastewater disposal wells becoming the norm in the state, Morris says Oklahomans should stay alert and expect the ground to shake much more in the months to come.

2 replies »

  1. Maybe it’s time to move the geology department to the school of liberal arts since they have have abandoned hard science for political spin, antidotal evidence and bad science. How can you look at 4 years (ignoring millions of years of events) and claim a geological event is outside of the norm? Have you seen the Arbuckles? You claim these events are unpredictable but if fracking was the cause you could predict when and where it should trigger an earthquake.


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