DALLAS– East Coast residents were jolted Friday by a magnitude 4.8 earthquake near Lebanon, New Jersey, with faint rumblings as far away as Baltimore and the Massachusetts-New Hampshire border. No life-threatening injuries or major damage were reported.
Here’s what you need to know about East Coast earthquakes.
Earthquakes large enough to be felt by many people are relatively uncommon on the East Coast. According to the United States Geological Survey, there have been about 20 earthquakes with magnitudes greater than 4.5 since 1950. That’s compared to more than 1,000 on the West Coast.
That said, East Coast earthquakes like Friday’s do happen.
“There is a history of earthquakes of similar magnitude in the New York region over the past few hundred years,” said Jessica Thompson Jobe of the USGS Earthquake Hazards Program.
In 2011, a magnitude 5.8 earthquake near Mineral, Virginia, shook residents of the East Coast across a wide area from Georgia to Maine and even southeastern Canada. The USGS called it one of the most widely felt earthquakes in North American history.
The earthquake cost $200 to $300 million in property damage, including to the Washington Monument in Washington, D.C.
The west coast lies at a boundary where parts of the Earth’s crust rub against each other, causing tension and slip along fault lines that cause earthquakes relatively frequently.
East Coast earthquakes like Friday’s are caused by compression over time of hard, brittle rock deep underground, according to Robert Thorson, a professor of earth sciences at the University of Connecticut. “It’s like having a big block of ice in a vise and you slowly turn the vise up,” he said. “You’ll get some crackles from it eventually.”
These East Coast earthquakes can be more difficult to locate. And they tend to affect a broader area. That’s because colder, harder rocks on the East Coast can better disperse an earthquake’s rattling energy.
The spread of cities along the East Coast also means that there are more people nearby who experience the effects of an earthquake.
“We also have population centers in much of the Northeast,” said Leslie Sonder, a geophysicist at Dartmouth College, “so a lot of people here are feeling the earthquake.”
USGS experts say there is a risk of aftershocks, which are expected after every earthquake, for weeks to months. They recommend paying attention to emergency messages from local officials.
To avoid shaking while sleeping, remove any furniture or objects that could fall and injure you or others.
If you feel like you are shaking, sit where you are. Cover your head and neck with one arm, crawl under a table for shelter and hold on. If there is no shelter nearby, grab your head and neck with both hands until the shaking stops.
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AP writer Pat Eaton-Robb contributed to this report from Storrs, Connecticut.
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