People all over the state of Oklahoma, and even some surrounding states, say they felt the 5.1-mag earthquake that shook the state Friday night.

The epicenter was in Lincoln County, near the town of Prague, but there have been 20 more earthquakes since that one.

Related Videos

1. Full Saturday Morning Coverage from News 9
2. Quake Damages Home In Meeker
3. Video Shows Earthquake Shaking Oklahoma Home
4. Prague Residents Recall Late-Night Earthquake

But what caused these earthquakes? Trey Davis with the Oklahoma Corporation Commission said they are looking at wells in the area, specifically wastewater injection wells, and for fracking operations.

"(The earthquake was) very near the 5.3 earthquake that occurred in that region back in 2011. We spent a couple hours last evening looking at activity in the area. This is not necessarily unusual for this area. Back in 2016 and 2017, we took action to shut in several wells, and we anticipate that's going to occur this time," Davis said.

He explained that sometimes, waste is injected into what's known as the Arbuckle, which runs across the entire state. However, Davis said that years ago they had begun pulling the wells out of the Arbuckle and to a shallower depth, limiting what could be injected.

As for the aftershocks, ranging from 2.9-mag. to 3.5-mag., Davis explained that they tend to happen either just north or just south of the epicenter. He said it's a very old fault line.

News 9's Deanne Stein talked to residents in Prague about what they felt Friday night.

5.1-Mag. Earthquake Felt Across Green Country

In Tulsa, the earthquake was felt all across Green Country. News On 6's Eden Jones talked to man who waits tables at The Tavern.

"I work over there at The Tavern downtown. I was just bussing some tables, and I felt some shaking. I thought it was like a parade or something going on, and then later I heard other people felt it, too, and they were saying something about an earthquake," he said.

This is a developing story. Refresh this page for updates.