An earthquake shook New York City on Friday morning, the U.S. Geological Survey said, causing no major damage but startling millions of people in an area unaccustomed to such tremors.

A 3.8 magnitude aftershock earthquake was reported by the U.S.G.S. later on Friday evening near Tewksbury, New Jersey. Click here to see the latest report from the U.S.G.S.

The U.S. Geological Survey reported a quake at 10:23 a.m. with a preliminary magnitude of 4.8, centered near Whitehouse Station, New Jersey, or about 45 miles (72 kilometers) west of New York City. U.S.G.S. figures indicated that the quake might have been felt by more than 42 million people.

New York City’s emergency notification system said in a social media post more than 30 minutes after the quake that it had no reports of damage or injuries in the city. The Fire Department of New York said on social media about an hour after the quake that it was “responding to calls and evaluating structural stability” but that there are “no major incidents at this time.”

While there were no immediate reports of serious damage, officials were checking bridges and other major infrastructure and Amtrak slowed trains throughout the busy Northeast Corridor.

In midtown Manhattan, traffic grew louder as motorists blared their horns on shuddering streets. Some Brooklyn residents heard a boom and their building shaking.

In Astoria, Cassondra Kurtz was giving her 14-year-old Chihuahua, Chiki, a cocoa-butter rubdown for her dry skin. Kurtz was recording the moment on video, as an everyday memory of the dog’s older years, when her apartment started shaking hard enough that a large mirror banged audibly against a wall.

Kurtz assumed at first it was a big truck going by. The video captured her looking around, perplexed. Chiki, however, “was completely unbothered.”

It was “pretty weird and scary” for Shawn Clark, who felt the quake in his 26th-floor midtown Manhattan office. Clark, an attorney, initially feared an explosion or construction accident. His colleague Finn Dusenbery worried the ceiling or even the building would collapse.

The earthquake slowed travel along the East Coast, with some flights diverted and traffic snarled on roads and rails for runway, bridge, and tunnel inspections. Flights to the Newark, New York and Baltimore airports were held at their origins for a time while officials inspected runways for cracks. At least five flights en route to Newark were diverted and landed at Lehigh Valley International Airport in Allentown, Pennsylvania, according to the flight tracking website FlightAware.

Solomon Byron was sitting on a park bench in Manhattan’s East Village. “I felt this vibration, and I was just like, where is that vibration coming from,” Byron said. “There’s no trains nowhere close by here or anything like that.” Byron said he didn’t realize there had been an earthquake until he got the alert on his cellphone.

At U.N. headquarters in New York, the shaking interrupted the chief executive of Save The Children, Janti Soeripto, as she briefed an emergency Security Council session on the threat of famine in Gaza and the Israeli drone strikes that killed aid workers there. In short order, diplomats’ phones blared with earthquake alerts.

As of noon, New York City had no indications of major safety or infrastructure problems from the earthquake, said Mayor Eric Adams, who said he didn’t feel the quake himself. City Buildings Commissioner James Oddo said officials would watch out for any delayed cracks or other effects on the Big Apple’s 1.1 million buildings.

The White House said in a statement that President Joe Biden had been briefed on the earthquake and was “in touch with federal, state, and local officials as we learn more.”

New York Gov. Kathy Hochul posted on X that the quake was felt throughout the state. “My team is assessing impacts and any damage that may have occurred, and we will update the public throughout the day,” Hochul said.

Among the affected travelers: Seton Hall University’s men’s basketball team, which was stuck in Indianapolis, where it won the National Invitational Tournament on Thursday. The team said its flight to Newark was being held because of the earthquake-related ground stop, likely delaying a welcome-home celebration scheduled for Friday afternoon on Seton Hall’s campus in South Orange, New Jersey.

Traffic through the Holland Tunnel between Jersey City, New Jersey, and lower Manhattan was stopped for about 10 minutes for inspections, the Port Authority of New York and Jersey said.

Earthquakes are less common on this side of the U.S. because the East Coast does not lie on a boundary of tectonic plates. But East Coast quakes can still pack a punch — its rocks are better at spreading earthquake energy across far distances.

“If we had the same magnitude quake in California, it probably wouldn’t be felt nearly as far away,” said U.S.G.S. geophysicist Paul Caruso.