Analysis of organic and fossil remains within the sediment samples taken from marshes along the Farm River in Branford and from Kelsey Island, about a mile away in Long Island Sound, indicated a much faster sea level rise in one area than in the other. The three Wesleyan University scientists realized that the two sites were on opposite sides of the Eastern Border Fault. This fault, which forms the eastern edge of the Connecticut River Valley, long considered to be dormant. Extensive research, including radiocarbon dating and sediment analysis, indicated that a pattern of slight upwelling in the Kelsey Island marsh has been followed by substantial earthquakes, which have occurred about once every 200 years over the past 1,200 years. The last significant earthquake to shake up the Connecticut River Valley was magnitude 4.4 and occurred in 1791-just about 200 years ago.
Current research indicates that such an upwelling is now occurring in the area.
Connecticut residents need not worry too much, however. Unlike the terrible recent tragedy in Turkey, damage would be relatively minor, limited to jiggling furniture, crashing china, and cracks appearing in foundations and chimneys. While structural damage could be extensive in some spots in the greater New Haven area, a magnitude 5 quake is not likely to collapse buildings or result in loss of life.