NYC is not prepared for a big earthquake, but does it need to be?

New York City has seen a pair of earthquakes in the last few days with minimal impact. A recent report finds a bigger earthquake could cause billions in damage to the city but thankfully, it’s not likely.

Recent earthquakes

A 2.7-magnitude quake shook the city on Tuesday. Centered in Hillsdale, New Jersey, there were no reports of any injuries or damage. People did report feeling the shake on social media.

It came just three days after a 3.0-magnitude earthquake that also caused no major damage or injuries. Sunday’s quake was centered in Hasbrouck Heights, which is not far from Hillsdale and a nearly 12-mile drive to Times Square.

“Both of them are small,” Weisen Shen, a geosciences professor at Stony Brook University, told Straight Arrow News. “But given the population density here, many people felt it.”

The cities lie along the Ramapo Fault Line, which marks the boundary of the Piedmont Plateau and the Atlantic Coastal Plain on the Atlantic Coast Tectonic Plate. It formed 200 million years ago and was very active at the time the Appalachian Mountains formed.

Odds of the big one

Unlike its famous west coast counterpart, the San Andreas Fault, the Ramapo Fault is now considered mostly inactive.

The San Andreas Fault is an “active strike-slip fault,” meaning two tectonic plates are actively sliding past each other, whereas the Ramapo Fault is in the middle of a stable tectonic plate and moves very little. And motion is what causes major quakes.

“If you look at the GPS motion along the San Andreas Fault, it is moving quickly,” Shen said. “It is moving relatively in large amounts every year, relative to the other side of the fault. But it’s just not happening here in our place.”

That means the odds of a serious magnitude earthquake like we’ve seen in California or recently off the coast of Russia and in Myanmar, are just not very high.

“Well, we’re just lucky, right? If you are talking about a large earthquake, you need plate motion, and you need to be close to the boundary of two plates that are moving relative to each other,” Shen said. “We are just not living in that place. Although we are at an edge of the continent, but it’s a passive boundary.”

Damage report

Lower odds are different than impossible. A damage report the city released in 2019 showed that just a 5.2-magnitude earthquake would cause nearly $4.7 billion in damage in New York City.

“If you’re looking at the building codes, we are not prepared for magnitude six or seven earthquakes,” Shen said.

That report mentioned a 5.2-magnitude earthquake that hit New York in 1884.

“If an earthquake like magnitude five hit very close to Manhattan, people will feel a much stronger shake and there will be more disruption to the civic system, like a running subway train can feel that earthquake,” Shen said. “We’ll have to shut down a large part of the city because of the shake. So, I can imagine a lot of economic impact to this region if a magnitude five earthquake happens.”

However, Shen stressed that most scientists don’t believe that’s likely to happen anytime soon.

Even with the odds low, it never hurts to prepare.

“The easiest thing is to educate the public, especially the kids in the school,” Shen said. “If there’s a shake coming in, don’t panic, stay still. Or if there’s a way of going into the open space, run for that, but don’t run crazily. Such education is always needed, and we also need to make sure that the region is equipped with a geophysical instrumentation network that can monitor the shaking all the time.”