• A magnitude 4.8 earthquake shook the northeastern U.S.
• The earthquake was felt from Boston down to Baltimore, according to the U.S. Geological Survey.
• In New York City, there were no immediate reports of injuries or damage, but the quake triggered numerous delays and temporary closures of transportation infrastructure in the area.

A magnitude 4.8 earthquake shook the northeastern United States on Friday morning.

The earthquake was felt from Boston down to Baltimore at 10:23 a.m. ET, according to the U.S. Geological Survey.

In New York City, where tremors were felt for more than 30 seconds, there were no immediate reports of injuries or damage, but the quake triggered numerous delays and temporary closures of transportation infrastructure in the area.

The epicenter of the quake was detected about 45 miles west of New York City, and 40 miles east of Allentown, Pennsylvania, in an area north of Whitehouse Station, New Jersey, according to the USGS.

Earthquakes of Friday's magnitude are relatively rare in the northeastern U.S., and the intensity and duration of Friday's quake startled people across the region. The quake was the third-largest recorded around the New York metropolitan region in nearly 75 years.

"Everyone @NYSE just gave each other a big look," CNBC's Carl Quintanilla tweeted from the New York Stock Exchange in lower Manhattan after the tremors occurred.

"I AM FINE," the Empire State Building's social media account X tweeted.

The National Tsunami Warning Center said there was no danger of a tsunami on the East Coast after the quake.

An aftershock with a 2.0 magnitude occurred at 11:20 a.m. ET in northern New Jersey.

The USGS said there was a 46% likelihood of another earthquake of magnitude 3.0 or greater in the next week.

The Federal Aviation Administration inspected runways at the three major airports in New York City and Newark, New Jersey. The agency briefly halted departures there, and as of 12:40 p.m. ET, the stop into Newark Liberty International Airport was lifted but flights were delayed about one hour.

United Airlines, which dominates the Newark airport, in a statement, said two United flights were diverted from Newark because of the ground stop there, and there were some minor delays in flights bound to JFK and LaGuardia airports in New York.

The carrier offered travelers booked to fly the chance to change their Newark, LaGuardia or Philadelphia flights without paying fees or a difference in fare if they can travel as late as next Thursday.

New Jersey Transit said its commuter rail service is subject to systemwide delays of up to 20 minutes.

The Port Authority for New York and New Jersey, which operates Hudson River crossings, said the Holland Tunnel connecting lower Manhattan to New Jersey was temporarily closed to traffic inspection.

New York Gov. Kathy Hochul in a tweet said, "My team is assessing impacts and any damage that may have occurred, and we will update the public throughout the day."

President Joe Biden later Friday said he had spoken to New Jersey Gov. Phil Murphy, "who thinks everything is under control."

"He's not too concerned about it," Biden said. "So things are alright."

New York City's emergency alert pushed out a warning to cellphones at around 11:46 a.m. ET warning that "aftershocks may be felt," but added, "NYers can continue usual activities."

— Additional reporting by CNBC's Leslie Josephs.