With plates colliding and breaking apart, numerous faults and earthquakes are inevitable. One of the most famous faults in Connecticut is the eastern border fault which begins south of New Haven (the exact origin is under water) and extends for 130 miles north to Keene, New Hampshire. Though inactive for 140 million years, it helped to create the Connecticut Valley. Prior to this sporadic earthquakes along this fault lowered the valley and raised the eastern hills. The Eastern Border Fault is further evidenced in the tilt of the valley outcrops—easily seen in the numerous roadcuts. The tilt of rock strata dips toward the east at about 15-25 degrees. This tilting has directly affected our mineral industry. Wherever erosion has caused a tipped basalt layer to jut out of the ground, a traprock ridge has formed. (Bell, 1985) (Little, 1986)
Wherever you are in Connecticut, an old inactive fault is no more than five miles away. Earthquakes can also strike in these area, far away from plate boundaries, and though the potential is there, Connecticut is at low risk for earthquakes to occur, until tectonic movements again interfere. (Johnston, Kanter, 1990)
From 1568—1989, 1214 earthquakes were recorded within New England. As far back as 1558, the native indians reported of quakes hitting Connecticut. In 1638, an earthquake frightened the pilgrims. In 1727, an earthquake was felt from Maine to Delaware. (NESEC, 1993)
The most famous area in Connecticut when it comes to earthquakes is Moodus. This is the only active region in our state today. The indians heard noises caused by swarms of quakes and created much folklore around them. Beginning in 1980, swarms of a few hundred quakes have occurred here, but these were mostly detected only by seismic instruments. (Little, 1985)
If an earthquake does hit Connecticut, the results will be somewhat different then that of a California quake. Our bedrock is harder and transmits seismic waves over an area from four to forty times greater than that of California. Also, more people will be at risk here due to lack of protective building codes. (Mass. Emergency Management Agency, 1994)
