NEW YORK (PIX11) – A 4.8-magnitude earthquake that shook New York City in April displayed “peculiar behavior” that raises questions about the potential threat of future earthquakes in the region, according to researchers.
In a new study, researchers from New York’s Columbia University and South Korea’s Seoul National University investigated the earthquake that struck Tewksbury in northwest New Jersey on April 5.
An estimated 42 million people felt the earthquake, according to the United States Geological Survey. Though damage from it was mostly minor, it was the biggest earthquake to occur in the region since a 5.2-magnitude earthquake near Brooklyn in 1884.
The April earthquake displayed some “peculiar behavior,” according to Won-Young Kim, a researcher at Columbia Climate School’s Lamont-Doherty Earth Observatory, who co-authored the new study.
When Kim and his colleagues visited the epicenter in New Jersey to investigate after the earthquake, they were surprised by what they encountered.
“We expected some property damage – chimneys knocked down, walls cracked or plaster fallen, but there were no obvious signs,” Kim said. “We talked to police officers, but they were not very excited about it. Like nothing happened. It was a surprising response for a magnitude 4.8 earthquake.”
Based on existing models, the earthquake should’ve done substantial damage at its epicenter in New Jersey, but it didn’t, according to researchers.
The researchers said the earthquake shook New York City harder than expected. They also said the earthquake’s shaking traveled “strangely far,” extending all the way to Virginia and Maine.
“Usually, earthquake shaking fades out in a more or less symmetrical bull’s eye pattern from the source. But that did not happen either; stronger than expected shaking extended far out, mainly to the northeast, and to a lesser extent other directions,” Columbia Climate School senior editor Kevin Krajick wrote in the press release.
The researchers investigated why the earthquake felt stronger away from its epicenter. Their findings suggested that the earthquake took place on a previously unmapped fault that runs south to north.
“The fault is not vertical, but rather dips eastward into the Earth at about a 45-degree angle,” Krajick wrote in the press release, adding that much of the earthquake’s energy “headed downward, along the fault’s dip, and continued until it hit the Moho. Then it bounced back up, emerging among other places under New York City, which was right in the way. Then the wave bounced back down and re-emerged further away in New England, somewhat weaker, and so on, until it petered out.”
Kim, the Columbia University researcher, said that the new study suggests the need to re-evaluate how shaking from any future sizable earthquake may be distributed across the region.
“Some that are not even that big could maybe focus energy toward population centers. If [the April] earthquake was just a little stronger, or a little closer to New York City, the effect would be much greater,” Kim said. “We need to understand this phenomenon and its implications for ground motion prediction.”
Finn Hoogensen is a digital journalist who has covered local news for more than five years. He has been with PIX11 News since 2022. See more of his work here.
