In 2012 a magnitude 4.0 earthquake was recorded in Hollis, Maine.
That’s the largest in Maine since modern instruments were installed in 1975.
But the state does not get many quakes, and the ones we do get probably aren’t felt by many people.
There have been many earthquake in Maine throughout history, some were estimated to be closer to 6, but those were centuries ago.
And the chances of another big one hitting Maine are really slim.
“There’s a very low probability,” said Maine State Geologist Robert Marvinney. “It’s not zero, but there is a low probability of earthquakes anywhere in Maine and there is low probability of a damaging earthquake.”
It may seem like earthquakes are becoming more common now, but there are factors that increase the chances of one being felt and therefore being recorded and reported.
“Information flies faster, more people are active and more people are aware,” said Dr. Bob Nelson Professor of Geology at Colby College. “And what something a lot of people lose sight of is there’s more people. There are 3 times as many people on planet earth, there are 3 times as many people in the United States as when I was born.”
There are a number of monitoring stations in Maine including one that students and staff at Colby College probably walk over having no idea it is right beneath their feet.
“This is the entire nerve center,” said Professor Nelson. “It’s like being in a wine cellar, it’s cold, solid concrete walls, the actual USGS receiver is under here and I don’t even want to mess with it because it is so sensitive, this looks like a piece of junk but it is equally as sensitive this is ours and this is a continuous line that runs all the way up into our department office if they ever want to set it up again so that we have one right there.”
The information is sent to the US Geological Survey in Denver, and Nelson said this facility will record quakes from around the world, and all of it helps piece together the size and location of the quake. “It tells you among other things, the earthquake occurred, such and such a distance from this location, so you can draw a circle and it’s somewhere on that circle, if it’s 40 miles out, we don’t know if that means Bangor, or Brunswick or Lewiston it’s somewhere out there, so you get another station say over at the University of Vermont and they say “Oh it’s 110 kilometers from us”, and you can draw a 110 kilometer circle from them and that’s only going to overlap our circle at two points, and then you get a third site and you get a unique solution. And instead of actually a circle you get a hemisphere where they actually interact below the surface tells you how deep it was.”
So while the chances for a damaging quake are slim in Maine, the state geologist says don’t throw all caution to the wind.
“The things that we suggest people do is things like secure oil tanks and water tanks in the basement to the walls so they are stable, don’t put heavy objects over places where people sit or sleep you know those are kind of the things people should think about in their own homes,” said Marvinney. “Because we could have something that rattles enough that I’m sure that magnitude 4 in Hollis knocked some things off of shelves and that kind of thing, so those are the things people should be most concerned about.”
To see the USGS up to the minute global earthquake map go to this website.