Oil drilling to blame for Oklahoma earthquake, experts say

Residents from Texas to Nebraska were awoken early Saturday by a 5.6-magnitude earthquake.

The earthquake’s epicenter was 8.5 miles northwest of Pawnee, Oklahoma.

Since the initial earthquake at approximately 7:02 a.m. CST, there have been multiple aftershocks, ranging in strength from a 2- to 4-magnitude.

According to reports, Pawnee suffered some structural damage and one person was injured.

>>Read: Strong earthquake rattles Oklahoma, felt in other states

Amber Mann, who lives in Oklahoma City, approximately 90 miles southwest of Pawnee, told Rare that the earthquake woke her “up out of a dead sleep. It sounded as though my house was coming apart, and I felt the need to brace myself.”

Another individual, Missy Masterson, who lives in Noble, Oklahoma, also told Rare that she was awoken by her whole house shaking.

“It was quite alarming to say the least," Masterson said. "We woke up to the whole house shaking. I thought at first my husband was playing a trick on me. But I soon realized he was not in the room."

Masterson went on to surmise as to why Oklahoma has been hit by so many earthquakes in the last few years.

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“I am not sure if this has anything to do with all the oil drilling or if it is the major fault line that runs down the central part of the U.S. But, either way, I do not like them.”

Masterson isn’t the only who thinks oil drilling is behind the increase in Oklahoma earthquakes.

While Saturday's earthquake is tied for strongest earthquake on record in Oklahoma, there has been a huge increase in seismic activity in the last few years. In 2013, there were 106 earthquakes; in 2015, there were 857.

Although the number of earthquakes in 2016 seems to be slowing down slightly, experts are still pointing to oil and gas production as a reason for the increase in seismic activity in recent years.

Oklahoma's energy and environment office posted a statement on its website, Earthquakes in Oklahoma, pointing part of the blame at wastewater created by oil drilling.

“While we understand that Oklahoma has historically experienced some level of seismicity, we know that the recent rise in earthquakes cannot be entirely attributed to natural causes. The Oklahoma Geological Survey has determined that the majority of recent earthquakes in central and north-central Oklahoma are very likely triggered by the injection of produced water [i.e., wastewater] in disposal wells.”

Republican Oklahoma Gov. Mary Fallin sent out a tweet after Saturday’s earthquake that said the state would be evaluating disposal wells near Pawnee.

Regardless of the reason for the increase in earthquake activity, some experts are concerned that one of these strong magnitude earthquakes will hit a large population area and cause substantial damage.

According to KFOR, Todd Halihan, a researcher with OSU, said, "It's unclear exactly how high we might go, and the predictions are upper 5-6 range for most things that I've seen. Underneath any of these urban areas, whether it's Stillwater, Cushing, Oklahoma City, Guthrie, these cities are not built to seismic standards. They're not in LA."