Some New Shoreham, Rhode Island, residents were shaken awake Sunday by an early morning tremor.
According to a preliminary report by the US Geological Survey, an earthquake happened at 3:21 a.m. about 27 miles south-southeast of Block Island and 6.2 miles below the surface. No damage has been reported.
But it’s not the first time – it won’t be the last – that the ground twitched in Southern New England. There have been 139 earthquakes reported in the area or off the East Coast since 1970.
Five mild tremors all under 1.9 on the Richter scale have been reported this year, and five were reported in 2020. There were 16 earthquakes in 2019, none greater than 3.0.
The strongest earthquake recorded near Rhode Island was a 4.7 with an epicenter four miles east of Narragansett Pier on Sept. 3, 1978.
On June 25, 1970, a 5.0 tremor happened 115 miles south of Rhode Island in the Atlantic Ocean.
Fourteen earthquakes have been reported, so far, Sunday across the US, including eight in Idaho, four in California, and one in Texas.
Southern New England earthquakes
The USGS says that New England has felt small earthquakes and “suffered damage from infrequent larger ones since colonial times.”
“The Boston area was damaged three times within 28 years in the middle 1700′s, and New York City was damaged in 1737 and 1884,” the USGS website reports. “The largest known New England earthquakes occurred in 1638 (magnitude 6.5) in Vermont or New Hampshire, and in 1755 (magnitude 5.8) offshore from Cape Ann northeast of Boston. The Cape Ann earthquake caused severe damage to the Boston waterfront. The most recent New England earthquake to cause moderate damage occurred in 1940 (magnitude 5.6) in central New Hampshire.”
The USGS says that earthquakes occur on a fault within bedrock, usually miles deep, although some New England quakes happen at shallow depths.
“Most of New England’s and Long Island’s bedrock was assembled as continents collided to form a supercontinent 500-300 million years ago, raising the northern Appalachian Mountains,” the USGS website reports. “The rest of the bedrock formed when the supercontinent rifted apart 200 million years ago to form what are now the northeastern U.S., the Atlantic Ocean, and Europe.
If you felt Sunday morning’s tremor, you can report it to the USGS’s “Felt Report” at https://earthquake.usgs.gov/earthquakes/eventpage/us7000fclr/tellus.