© 2024 Connecticut Public

FCC Public Inspection Files:
Public Files Contact · ATSC 3.0 FAQ
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Why you could feel the New Jersey earthquake from hundreds of miles away

A blue map shows a small yellow dot around central New Jersey
USGS Earthquake Hazards Program
Public domain
When a relatively small 4.8 magnitude earthquake hit New Jersey, people as far away as Michigan, Quebec and Maine felt a rumble.

Just after 10 a.m., Keith Klepeis was writing a paper at his desk in Essex Junction, when he heard a low rumble, like a truck. Then, he noticed his computer monitor looked like it was twisting. “A truck wouldn't do that, so that's what gave it away for me,” he said.

Moments earlier, a relatively small earthquake hit New Jersey. Klepeis, a geologist at the University of Vermont, realized what he was experiencing: the initial fast waves that can produce a sound, followed by slower waves that move like ripples.

Small earthquakes are fairly common along the east coast, from old faults leftover from ancient geologic activity, like when the Appalachian Mountains formed or North America drifted away from Europe and Africa.

"There are still remnants of that past activity buried underneath the ground. And they whisper every once in a while and say, 'remember, I'm still here.'”
Dave West, Middlebury College

But we don’t usually feel them.

“It's definitely really exciting,” said Dave West, a geologist at Middlebury College who studies ancient faults. “It kind of lets you know that the earth is alive.”

Hundreds of millions of years ago, this area had massive earthquakes and volcanic eruptions, he said. “There are still remnants of that past activity buried underneath the ground. And they whisper every once in a while and say, 'remember, I'm still here.'”

There are a number of theories about the source of this seismic energy so far from a plate tectonic boundary.

“This is all speculation, but I could think that possibly those stresses might be due to the rebounding of the earth’s crust after the ice age,” said Leslie Sonder, a geologist at Dartmouth College.

Even thousands of years after the glaciers receded, the earth’s crust might still be springing up, after being pressed down by so much weight. “That slow rebound might cause enough stress to cause the occasional earthquake.”

Whatever the cause, we can detect this geologic activity very quickly because of a network of instruments spread out all over the world, including New England, that pick up sound and sense motion in the ground. Those stations can triangulate where and how deep underground an earthquake occurred.

While most earthquakes along the east coast aren’t very big, they can be felt hundreds of miles away because of the geology here. Rocks that make up the Appalachians are older, cooler and more dense than much of the geology of the western U.S.

“What that does is it allows the earthquake waves to propagate a lot farther,” said Klepeis, from the University of Vermont.

“That's why me, sitting up here in Vermont, I can feel those surface waves really strongly, even though the source was in New Jersey.”

Have questions, comments or tips? Send us a message.


Lexi covers science and health stories for Vermont Public.

Stand up for civility

This news story is funded in large part by Connecticut Public’s Members — listeners, viewers, and readers like you who value fact-based journalism and trustworthy information.

We hope their support inspires you to donate so that we can continue telling stories that inform, educate, and inspire you and your neighbors. As a community-supported public media service, Connecticut Public has relied on donor support for more than 50 years.

Your donation today will allow us to continue this work on your behalf. Give today at any amount and join the 50,000 members who are building a better—and more civil—Connecticut to live, work, and play.

Related Content