The earthquake struck at the orange dot inside the colored, concentric circles. Image: USGS
An earthquake struck this morning in southern New Hampshire, not far from the border with Massachussetts north of Boston. According to USGS, at 10:13 am today, a weak magnitude 1.8 earthquake struck near Kingston from a depth of 5.0 km. While the earthquake was weak, almost 2 dozen people used the “Did you feel it?” website reporting tool to let USGS know they felt or heard the earthquake.
USGS says that earthquakes with a magnitude of 2.0 or less are rarely felt or heard by people, but once they exceed 2.0 , more and more people can feel them. While damage is possible with magnitude 3.0 events or greater, significant damage and casualties usually don’t occur until the magnitude of a seismic event rises to a 5.5 or greater rated event.
Today’s earthquake joins other weak earthquakes that have struck recently in the eastern United States; they include New Jersey on Friday, Georgia on Sunday, and Tennessee yesterday. None of the earthquakes appear to be directly tied to the others.
New England is no stranger to earthquakes; this map shows the epicenter of every earthquake from 1975 to 2017. Image: NESEC
People in New England, and in its geological extension southward through Long Island, have felt small earthquakes and suffered damage from infrequent larger ones since colonial times. Moderately damaging earthquakes strike somewhere in the region every few decades, and smaller earthquakes are felt roughly twice a year. 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 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.
According to the Northeast States Emergency Consortium, there were 320 earthquakes between 1638 and 2016; earthquakes that struck in 1638 and 1940 produced damaging results.
