The epicenter was just southwest of Salt Lake City and about 2.8 million in the state probably felt the quake, the U.S. Geological Survey reported.
There were no initial reports of major damage to buildings or injuries, said Utah Emergency Management spokesman Joe Dougherty.
I know the last thing we need right now is an earthquake, but here we are, and it sounds like aftershocks are likely. The City is assessing the situation now and I’ll circle back with an update when I have it. Be safe. #utpol #slc— SLC Mayor Erin Mendenhall (@slcmayor) March 18, 2020
Operations at Salt Lake City International Airport came to a halt and the control tower and concourses were evacuated, the airport tweeted. The quake also shut down the light rail service for Salt Lake City and its suburbs.
Residents reported feeling shaking across a 100-mile (160 kilometer) area, with the heaviest impact in Salt Lake County, officials said.
Some residents ran from their homes and into the streets as they felt the earthquake shake buildings for 10 to 15 seconds.
The quake knocked pictures from walls and dishes from shelves, and people reported feeling it in the neighboring states of Colorado, Idaho, Wyoming and Nevada. Gov. Gary Herbert warned people to stay away from downtown Salt Lake City while officials assess damage.
About 55,000 people lost electricity in the Salt Lake City area, said utility Rocky Mountain Power.
The road to the Salt Lake International Airport was closed and officials asked people not to head to the airport.
It was the largest earthquake to hit Utah since a 5.9 magnitude quake shook southern Utah in 1992, according to Utah Emergency Management.
Most shaking was reported in the Salt Lake County area, near the epicenter in the Salt Lake City suburb of Magna but the quake was felt 80 miles away (130 kilometers) in the Utah city of Logan.
After the initial quake struck at 7:09 am, the geological survey recorded four smaller quakes over the next 23 minutes, ranging in magnitude from 3.7 to 3.9.
It is very likely that you will feel aftershocks today.— Utah Emergency Mgmt (@UtahEmergency) March 18, 2020