Can a Large Earthquake Hit Massachusetts?

When you see the word “earthquake,” you’re most likely thinking “California.” At least you probably would have before this past Monday when a tremor in Connecticut was felt across New England, including parts of Massachusetts.

That earthquake, which measured at a 3.3 magnitude, set off more than a dozen others between Connecticut and Rhode Island in what seismologists call a “swarm.”

The latest quake struck in Plainfield, CT on Thursday morning, Jan. 15, around 4:39 a.m., according to the U.S. Geological Survey (USGS).

Plainfield Police have received more than 300 calls about the earthquakes this week, according to The Boston Globe. There seems to be a simple explanation for all those calls: people aren’t used to earthquakes and therefore aren’t sure what to do.

But despite New England’s “that doesn’t happen here” understanding of earthquakes in the region, the earth tremors here more often than you’d think.

Data taken from seismometers that Boston College’s Weston Observatory staff set up throughout New England show earthquakes happen almost every day, we just usually don’t feel them.

Earthquakes too small for humans to notice are called microseisms, according to The New Hampshire Department of Environmental Services, and are thought to be a byproduct of human interference such as drilling for gas and mining.

Larger tremors, anything with a 3.0 magnitude or higher, are what we typically feel and refer to as “earthquakes.” These tremors happen most often when stress builds up on a fault line, a fracture in the Earth’s crust, and is then released. This causes rocks on either side of the fault to slip past each other and sends a wave of energy throughout the ground.

According to the USGS, “the magnitude of an earthquake is related to the length of the fault on which it occurs -- the longer the fault, the larger the earthquake.”

New England sits on a spiderweb of faults, according to the USGS. But faults in Massachusetts are small compared to those in western states like California, meaning the likelihood of a devastating quake is slim. The state’s biggest recorded earthquake happened more than 250 years ago, off the coast of Cape Ann in 1755.

That earthquake measured in at a 6.2 magnitude and caused chimneys in the area to crumble, according to a newspaper of the time. But John Ebel, senior research scientist at the Weston Observatory, doesn’t expect to see anything close to that magnitude during the current swarm.

“There is less than a 1 percent chance of getting anything larger than the 3.3-magnitude quake,” Ebel told The Boston Globe.

In other words, you shouldn’t worry that Massachusetts will be hit with an earthquake so big that the earth opens up and swallows you whole. The USGS disproves that myth with two simple sentences.

“If the fault could open, there would be no friction. Without friction, there would be no earthquake.”

Image via Wikimedia: Damage caused by a magnitude 7.5 earthquake in Guatemala in 1976.

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