A small earthquake shook the earth in Western Massachusetts this morning.
The US Geological Survey reports that a 1.4-magnitude earthquake was recorded at about 12:34 a.m., 4 miles northeast of Northampton, in the town of Hatfield.
The temblor was centered at a depth of about 6.8 miles.
A dispatcher at the Northampton police said she hadn’t gotten any calls about people feeling the quake.
But about 100 people had called in by mid-morning to report feeling the quake at the Weston Observatory, the Boston College geophysical observatory, a staff member said.
Usually, earthquakes of this magnitude are not felt, except right above it, said John Ebel, director of the observatory and professor of geophysics. He also noted that because the earthquake occurred in the early morning hours, someone would have to have been awake to feel it.
“People in bed probably would have slept right through it,’’ he said.
A 0.8-magnitude aftershock was recorded approximately 10 minutes after the initial quake, said Justin Starr, a research assistant at the Weston Observatory.
Starr said the quake was an intraplate earthquake. All earthquakes on the East Coast are this type because the region is not on the edge of a tectonic plate, he said.
Such quakes are caused by stress that develops at weaker zones in the crust. There are two theories about why they happen, he said: Either a brand-new oceanic crust is being formed in the middle of the Atlantic that’s pushing the North American plate in on itself, or the ground is slowly “bouncing’’ back into equilibrium after pressure from glaciers during the last Ice Age.