Seismologists are working to understand what caused this week's cluster of earthquakes in Edmond, and how to prevent future events.
The Oklahoma Geological Survey’s best theory right now is that these earthquakes are a delayed response from wastewater injection in years past, but to better understand this trend the seismologists need help.
From more than 900 in 2015, to 600 in 2016, to a projected total of around 300 in 2017, Oklahoma earthquakes are steadily happening less frequently each year. Seismologists say that is largely due to the shut in of wastewater disposal wells across the central portion of the state, but the already-injected water is still squeezing through the faults as it makes its way towards the earth's core.
“We’re beginning to see clusters of small earthquakes happening before some of these large earthquakes that give us a hint if we can see those ahead of time,” Dr. Jeremy Boak said.
A group of concerned citizens protested outside the Oklahoma Corporation Commission Friday morning, calling for the state to do more to regulate the oil and gas industry. Many of those companies have already moved to western Oklahoma, though, where they are finding more product with fewer concerns.
“The water quality in that part of the state is totally different and the water amount that’s produced is significantly less,” said Chad Warmington, president of the Oklahoma Oil and Gas Association.
Less brackish water makes it easier and cheaper to recycle, as the Newfield Corporation found when they launched their new facility in Kingfisher.
Still, OGS scientists believe sporadic events like this week's cluster could be the "new normal" until the already-injected water settles over time. They would be better able monitor the central Oklahoma interest area with more seismometers, but right now they are reliant primarily on devices owned by other agencies like the USGS.
“They’ve been pulling instruments out of here to go to look at other regional areas, just at the time when they’re telling us the risk is as high here,” Boak said.
The cost for an array of their own, though, is an estimated $3.5 million, not quite pocket change for a struggling state economy. While it is a big ask, OGS believes having more monitoring stations with newer technology may eventually help them predict large earthquakes by being able to see the smaller foreshocks in real time, and that would be a global first.