CUSHING, Okla. — Several aftershocks have followed a damaging earthquake in central Oklahoma which hit the small city of Cushing, a crude oil storage hub and the southern terminal of the Keystone Pipeline.

A magnitude 5.0 temblor struck at 7:44 p.m. Sunday one mile west of Cushing and 16 miles east-southeast of Stillwater, according to the U.S. Geological Survey.

No one was injured, but residents of Cimarron Tower, an appartment complex for affordable housing for the elderly, were evacuated. Power was out in the area for up to an hour. Public schools were closed on Monday in order to assess damages, NPR reported.

According to an Associated Press report, dozens of buildings were damaged in Cushing, but Gov. Mary Fallin has said there’s no damage to storage tanks at the oil storage terminal.

The U.S. Geological Survery said aftershocks are a risk and some have already occured in the Cushing area. 

“The magnitude 5.0 earthquake has already triggered several aftershocks of magnitudes less than 3,” Oklahoma Geological Survey Director Jeremy Boak said. “Aftershocks are earthquakes that occur following a large earthquake, in the same general area as the earthquake, ranging from days to even a few years. The likelihood of an aftershock being larger than this earthquake is about 5 percent.”

The area of the quake has been an active zone of seismicity since 2015, Boak said.

At least six aftershocks measuring between magnitude 1.7 and magnitude 2.6 occurred in the area of the initial quake, OGS records show.

Also early Monday, two earthquakes were recorded in the Fairview area and another one near Nicoma Park.

A magnitude 3.8 temblor was recorded at 1:34 a.m. Monday 19 miles northwest of Fairview and 47 miles west of Enid. It was 3 miles deep, the USGS reported.

At 2:46 a.m. Monday, a magnitude 2.9 quake occurred 1 mile north-northeast of Nicoma Park and 6 miles northeast of Midwest City. It was 4 miles deep.

A magnitude 3.2 earthquake was recorded at 7:43 a.m. Monday 14 miles northwest of Fairview and 42 miles west of Enid. It was 3 miles deep.

The Oklahoma Corporation Commission’s Oil and Gas Division is working on an action plan to further modify Arbuckle disposal well operations in the area of the magnitude 5.0 earthquake, and details will be announced as soon as a plan is finalized, according to an OCC advisory.

There have been 582 magnitude 3.0 or greater earthquakes recorded in the state this year, including 19 measuring magnitude 4.0 or greater and three measuring magnitude 5.0 or greater, USGS records show. Last year, as of Nov. 7, 2015, there had been 739 magnitude 3.0 or greater quakes, including 22 measuring magnitude 4.0.

State Rep. Corry Williams is calling the earthquakes manmade and is urging the Oklahoma Corporation Commission to stop using injection wells, which experts believe are to blame for the rise in seismic activity.

“[Many scientists] have told us that what we’re doing in this state is extremely dangerous,” Williams said. “We are willfully ignoring the evidence. The peer-reviewed research says that high-volume, high-pressure injection is causing these earthquakes.”

In case of future quake activity, Boak advised Oklahoma residents to protect themselves from falling objects by dropping to the ground, covering head and neck and holding onto any sturdy cover.

Jessica Miller writes for the Enid, Oklahoma News & Eagle