A Brief History Of The Rare Long Island Earthquake

LONG ISLAND, NY — In the wake of the 4.8-magnitude earthquake that hit New Jersey and could be felt in New York and on Long Island Friday morning, locals are wondering: when was the last time this happened?

Compared to the incidence of earthquakes on the West Coast of the United States, East Coast earthquakes of a significant magnitude are rare. Even more rare is the occurrence of quakes with the epicenter on the island itself, with the latest over magnitude 2.5 being reported in March 1992, when a 2.8 trembler struck two kilometers southwest of Napeague.

If you go a bit wider geographically, the biggest quake affecting the area to date is perhaps the magnitude-5.3 tremor that struck Coney Island in New York City in 1884, according to the U.S. Geological Service. That's the same magnitude as the first and still one of the biggest earthquakes ever recorded with the epicenter in the area — the one that hit the greater New York City Area in December 1737.

Most locals, depending on where exactly they live, probably recall feeling their last earthquake in either August 2011 or April 2019.

On August 23, 2011 — around the time Hurricane Irene hit — a magnitude 5.8 earthquake hit Virginia and was felt in several surrounding states, including in New York and on Long Island. It is also still the largest tremor to hit the East Coast in the last century, according to the USGS.

Years later, on April 9, 2019, a much smaller but closer trembler struck near Southampton.

Since 1950, 40 other earthquakes of magnitude 3 and larger have occurred within 250 kilometers of Friday's earthquake, the USGS said.

So what exactly is an earthquake? According to the USGS, an earthquake is what happens when "two blocks of the earth suddenly slip past one another" as the earth's crust adjusts over time. They usually occur at a fault zone, where tectonic plates collide.

"These impacts are usually gradual and unnoticeable on the surface; however, immense stress can build up between plates," according to National Geographic. "When this stress is released quickly, it sends massive vibrations, called seismic waves, often hundreds of miles through the rock and up to the surface."

Friday's earthquake occurred in a region where faults have been previously identified and may be reactivated at any time, according to the USGS.

Around 80 percent of all the planet's earthquakes occur along the rim of the Pacific Ocean due to the amount of volcanic activity, National Geographic reported. But earthquakes — most very small, some deadly — have happened on the East Coast for centuries.

"Earthquakes are uncommon but not unheard of along the Atlantic Coast," the USGS wrote on X, formerly known as Twitter. "There's no active plate boundary between the Atlantic & N. American plates, but there are stresses."

The largest earthquake ever recorded in the eastern United States struck in 1886, when a magnitude-7.0 earthquake killed 60 people in Charleston, South Carolina, Forbes reported.