A magnitude-6.3 earthquake struck off the Oregon coast Thursday morning, authorities say.

The quake happened approximately 184 miles west of Coos Bay about 8:08 a.m., according to the U.S. Geological Survey. A tsunami is not expected. The agency said the quake had a depth of more than 3 miles.

Although hundreds of people online reported they felt the quake, dispatchers in Coos Bay said they didn’t get a single call about it. Margaret Barker, the Port of Coos Bay’s external affairs manager, said no one at the port reported feeling the quake.

“Oddly enough, I didn’t hear about it until a couple of hours ago.”

But Barker said the port has several measures in place to prepare for earthquakes and tsunamis. There have been a few moderate-strength earthquakes off the central and southern Oregon coast this summer.

“It’s obviously on our minds, and we hear about it a lot,” Barker said. “If we’re going into meetings, we have a safety briefing and go over emergency exits, gathering spots, evacuation routes.”

Barber said the port is also part of a group called the Harbor Safety Committee, which includes other agencies like the Coast Guard and terminal operators for the port. The committee meets to talk about different safety issues.

One of the biggest concerns should an earthquake strike is how people in different areas would communicate with each other, Barber said. The county has taken a lead on coordinating communications should disaster strike.

Magnitude-6.3 earthquakes are considered strong, according to the U.S. Geological Survey.

Seismologists say the likelihood of “the big one,” a major earthquake and tsunami that are expected to hit the Pacific Northwest when the Cascadia Subduction Zone rips, occurring in the next 50 years is 10 to 14 percent. It’s a good idea to prepare, packing earthquake kits at home and work with emergency food and water, and planning meeting places for after the quake happens.

-- Jim Ryan and Jayati Ramakrishnan

jryan@oregonian.com; jramakrishnan@oregonian.com

Visit subscription.oregonlive.com/newsletters to get Oregonian/OregonLive journalism delivered to your email inbox.