Earthquake that rocked NYC was caused by little-known 185-mile fault line in New Jersey, experts say

Deep in the ground of northwestern New Jersey is a stretch of a 185-mile-long fault, which triggered the 4.8-magnitude earthquake that rocked New York City Friday, experts told DailyMail.com.

The ‘epicenter’ sits on the Ramapo Fault, the longest system of cracks in the Northeast, which formed 400 million years ago - much older than California's 28-million-year-old San Andreas.

But the fault also triggered a small quake near the epicenter last month. 

The system spans from upstate New York, through New Jersey and down into Pennsylvania - and experts have long believed it has the potential to produce a major seismic event.

Kenneth Miller, a professor at Rutgers University, confirmed to DailyMail.com that the Ramapo Fault was 'certainly what caused Friday's earthquake,' while nothing that a 6-to 7-maginitude quake would have been devastating to the northeast.

'A 6- to 7-maginitude earthquake is possible, but seems very unlikely, said Miller, while explaining the Ramapo Fault line does not trigger anything above a magnitude 3 on average.

The system, however, produced a rare interior-related seismic event, which account for less than 10 percent of the natural disasters that hit our planet each year.

An intraplate earthquake occurs within the interior of the tectonic plate, while a most other strike on the boundary of the tectonic plate. 

'The earthquake was rated as a 4.7 or 4.8 by the United States Geological Survey, which is enough to rattle the walls, but generally not produce severe damage,' said Miller.

'The earthquake occurred on the Ramapo Border fault at an estimated depth of  4.35 miles with an epicenter near Lebanon.'

A fault line is a place where there is a long break in the rock that forms the surface of the earth and where earthquakes are more likely to happen.

Dr J Bret Bennington from Long Island’s Hofstra University also named the Ramapo Fault as the culprit.

‘It is possible that a little bit of that strain energy along that fault was released and we had a mild earthquake,’ Bennington shared in a video shared on TikTok.

The earthquake  was the strongest to come from New Jersey since 1738 when locals experienced a 5.3-magnitude

New Jersey's last significant earthquake was a magnitude 2.3 on August 30, 2022, in the White Meadow Lake section of Rockaway Township in Morris County, also along the Ramapo Fault.

But Hunterdon County felt a smaller 2.2-magnitude just last month on March 15, 2.5 miles north-northeast of Whitehouse Station.

An assessment from Michigan Tech University showed that people typically do not feel quakes with a magnitude of 2.5 or less. 

Those from 2.5 to 5.4 are often felt but only cause minor damage.

And buildings and other structures can experience damage when a 5.5 to 6.0 strikes.

'New jersey building codes are not designed for true earthquakes,' Miller said.

'Any tall building could withstand a 6-magintidue, but a 7 would be a concern.'

Miller explained that the Ramapo Fault was created when continents first started pushing together hundreds of millions of years ago.

'[The system] reactivated 200 million years ago, causing about four miles of movement,' he explained.

'It then stopped around 198 million years ago when the Atlantic Ocean formed.

The fault link continued with activity, but has since slowed down to minor movements. 

Miller said there was a minor 2-maginitude aftershock felt in Bedminster at around 12pm ET - and there could be more to follow that 'nobody will notice.'