On the morning of Jan. 27, students at the University of New Hampshire experienced sudden shaking as a magnitude 3.8 earthquake struck off the coast of Southern Maine. UNH quickly issued an alert acknowledging reports of an earthquake, assuring students and faculty that they were monitoring the situation.
According to Sophie Coulson, assistant professor of Earth Sciences at UNH, earthquakes of such magnitude in this region are relatively uncommon because of their position in the middle of a tectonic plate.
“An earthquake essentially happens when pressure builds up in the top layer of the earth, in the crust,” Coulson explained. “Eventually, when that pressure is built up enough, the rock will break to accommodate that pressure.”
Unlike earthquakes that occur at plate boundaries, the recent tremor was classified as an intraplate earthquake. These occur when stress builds up within a tectonic plate, often reactivating old faults.
“On the East Coast, for us, it’s a little more unusual because we’re actually in the middle of a tectonic plate,” Coulson said. “But although we’re further away from the edges of the tectonic system, we’re still subject to pressure from that system.”
While small earthquakes happen more frequently in the region, most go unnoticed due to their low magnitude.
“We do actually have frequent, smaller earthquakes—things like magnitude 2 earthquakes—that we don’t feel,” Coulson noted. “But in terms of ones similar in size to this, we probably see earthquakes of this size every five years or so.”
Coulson admitted that she missed feeling the tremor while preparing for class. “Disappointingly, I actually didn’t feel it,” she said. “I went down to lecture to about 80 students, and I think of those students, about 95% of them felt it. So I was a little disappointed I didn’t, to be honest.”
For those who felt the shaking, Coulson emphasized standard earthquake safety precautions.
“The key advice with an earthquake is to stop what you’re doing, get under a desk or something that can protect you,” she advised.
However, Coulson reassured that there was no need for concern, explaining that the earthquake’s impact was minimal.
“Directly in the location of the fault where the earthquake happened, the ground may have moved by a couple of centimeters, but it’s not likely to have wider effects further away,” she explained. “Here, we shouldn’t worry too much about it.”
Instead, Coulson pointed out that natural disasters of greater concern in the Durham and Portsmouth area are related to climate change. “We more want to focus on the impacts of climate change – thinking about how things like sea-level rise and storm surges might affect our future,” she said. “Flooding is something we have to be more prepared for than earthquakes.”
For many on the UNH campus, the earthquake was a rare reminder of Earth’s natural forces, even in an area where such events are uncommon. Although it was briefly disruptive, campus quickly returned to normal following the event.
