A 4.0 magnitude aftershock hit a town near the epicenter of Friday’s quake in New Jersey hours after the morning temblor — and was strong enough to rock the chandeliers at City Hall in Manhattan.
The early-evening aftershock struck in Gladstone, NJ, close to the 4.8 magnitude morning quake in Lebanon, NJ, which occurred near an ancient crack in the Earth’s crust known as the Ramapo fault.
A City Hall worker came running into the press room in Manhattan to check on journalists because of the aftershock, which occurred about 50 miles away and caused the municipal building’s majestic light fixtures to sway.
Experts warned there is a nearly 40% chance that a slew of other significant tremors hitting 3.0 magnitude could also occur in the region within the next week. The Ramapo fault, which runs from New Jersey to Pennsylvania, is the longest in the Northeast.
Friday evening’s substantial aftershock near it also could be felt in Brooklyn, shaking buildings and renewing fears by residents.
Follow The Post’s coverage on the NYC and tri-state earthquake
The morning’s 4.8 magnitude quake had already rattled the New York metro area when it hit near Lebanon about 10:30 a.m.
The quake was felt relatively far and wide because of the Earth’s crust in that area, experts said
“Earthquakes on the East Coast are felt four to five times further than a similar-strength quake on the West Coast. The rock is harder, and seismic waves travel further before they attenuate, so more people will feel it than if it was a similar earthquake in California,” said USGS seismologist Paul Earle.
Dr. Shannon Graham, assistant physics professor at The College of New Jersey, told The Post that quake was likely the result of stored-up stress in the Earth’s crust along “ancient plate boundaries,” which formed hundreds of millions ago when the African and North American land masses combined and then broke apart.
“Think of it like bending a stick. You’re storing energy in the center of the stick, and once your strength overcomes it, it snaps,” she said. “That’s what happens in the Earth. You pick a zone of weakness, which is where slip will occur along rocks.”
Graham said an earthquake with the potential to cause significant damage on the East Coast is “not impossible, but unlikely.”
Residents in a Newark, NJ, building had to evacuate after the quake causes structural damage to the home.
At least 10 more minor aftershocks had already also happened in areas near the epicenter of Friday’s quake, including a 2.0-magnitude one in Bedminster, NJ, around 1 p.m., the USGS said.
“Previously we’ve only seen earthquakes of magnitude 2, which is 100 times less severe than this one,” said Borys Hayda, managing principal at the structural engineering firm DeSimone Consulting Engineers, to The Post on Friday.
“It’s a significant earthquake, especially for this region,” he said of Friday’s temblor.
The earthquake was the strongest to originate around the New York area since 1884.
The United States Geological Survey estimated that there is a 38% chance of experiencing up to 10 aftershocks of 3.0 magnitude in the region within the next week. There is a 8% chance for up to one magnitude 4.0 and a 1% chance of a magnitude 5.0, according to its website.
There is a 46% chance of a 3.0 magnitude aftershock to hit within a month.
