May 16: The Largest Earthquake in Connecticut History


On this day in 1791, Connecticans were rattled by the largest earthquake ever recorded in Connecticut history.  Two powerful tremors, occurring within minutes of each other, terrified residents and damaged homes throughout the central part of the state.  Reports from as far away as Boston and New York City confirmed the presence of seismic activity that very same evening.

While it was impossible to precisely determine the epicenter of the quake at the time, many residents claimed the seismic activity emanated from the Moodus area, part of the town of East Haddam in south-central Connecticut.  The land surrounding Moodus had a long and infamous history of producing strange, unsettling seismic booms — a history that predated English settlement.  Indeed, the name “Moodus” came from the Native American name Machimoodus, commonly translated as “place of noises.”

One contemporary eyewitness account described the 1791 earthquake and aftershocks as follows:

“It began at 8 o’ clock, P.M. with two very heavy shocks in quick succession. The first was the most powerful; the earth appeared to undergo very violent convulsions. The stone walls were shaken down, chimnies [sic] were untopped, doors which were latched were thrown open, and a fissure in the ground of several rods in extent was afterwards discovered. Thirty lighter ones succeeded in a short time, and upwards of one hundred were counted in the course of the night.

This shock was felt at a great distance. It was so severe at Killingworth [modern-day Clinton], about twenty miles distant, that a Capt. Benedict, who was walking the deck of his vessel, then lying in the harbor of that place, observed the fish to leap out of water in every direction as far as his eye could reach. The atmosphere was perfectly clear and pleasant, and the moon, which was near its full, shone remarkably bright. On the night of the 17th, six more were observed. The atmosphere was still clear and warm.”

Modern seismologists estimate that the 1791 earthquake would have registered between a 4.4 and 5.0 on the Richter scale.   The “Moodus Noises” and strange seismological activities continue to this day;  as recently as January 2015, scientists recorded a notable “swarm” of minor earthquakes in the area.

Further Reading

Largest Earthquake in Connecticut,”

Justin Starr, “Earthquake Sounds: The Legends, Folklore, and ‘Noises’ of Moodus, CT,” Boston College’s Weston Observatory

History of Earthquakes in Connecticut,” (Northeast States Emergency Consortium)