Swarm of tremors arouses curiosity but little concern

A series of minor earthquakes that rattled the area around Berne in Albany County over the past few days is not a signal of worse things to come, according to a seismologist monitoring the situation. But they have intrigued scientists.

“There is no reason to expect something worse is coming,” said Art Lerne-Lam of Lamont-Doherty Cooperative Seismographic Network. “The only significance is that earthquakes can happen anywhere and that earthquakes that happen in the Northeast are small, based on the history and knowledge we have,” he said.

The network, an affiliation of more than 35 colleges and universities, monitors earthquakes that occur primarily in the northeastern United States. It recorded eight earthquakes about 21 miles west of Albany on Sunday and Monday.

None was greater than magnitude 2.2, a minor release of energy, Lerne-Lam said. “It might have felt like a large truck going by,” he said.

Berne Supervisor George J. Gebe Jr., who has lived in Berne for some 40 years, said he does not recall experiencing earthquakes in the town. Still, he remained unfazed by the latest tremors.

“We felt it at the house and we moved on. It is not like we are on the West Coast. If they were more threatening we would worry about it,” he said.

Gebe said the earthquakes caused no local damage. “Things are good,” he said.

Lerne-Lam called the series of earthquakes in Berne a “swarm.” Swarms happen occasionally throughout the Northeast, he said. “It is not completely random. There are faults everywhere because we are near the Appalachian Mountains,” he said.

The faults are old and can be weak and can break into minor earthquakes, Lerne-Lam said. He said the minor earthquakes indicate the crust is under stress but that the hazard is low.

Earthquakes of magnitude 2.5 or 3 are more likely to crack chimneys, foundations and old masonry, he said.

Professor John Garver, chairman of the Union College geology department, said the swarm has piqued the curiosity of scientists. “We do not know what is going on,” he said. “The most important thing we can do to understand this is to monitor the situation. We need to have seismic resources set up and have the instruments on the ground so we can listen.”

Garver called the Berne tremors “intraplate earthquakes,” as New York is stable geologically because it does not sit on a tectonic plate boundary. “In general, in earth sciences, when we have earthquakes within the plate, it is puzzling how they form,” he said. “That is why everyone is scratching their heads on the Berne swarm.”

Lerne-Lam said should the tremors continue, the network may place some instruments in Berne. “They are interesting and we should study them. We might learn the location and structure of a particular fault and learn something about the stress field of the crust in the location,” he said.

Lerne-Lam added that studying the Berne earthquakes would also allow seismologists to calibrate their recording instruments, “so we can do better the next time.”

He said seismologists can’t predict earthquakes, but “we can learn more where they might occur. If we are lucky we could tell you with some probability of when they would occur.”

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