Northeastern Section - 36th Annual Meeting (March 12-14, 2001)

The Lamont-Doherty Cooperative Seismograph Network (LCSN) monitors earthquakes in Eastern United States and consists of four nodes located at SUNY Potsdam, Middlebury College, VT, Delaware Geological Survey and the LCSN at Palisades, New York. The Potsdam node located in the St. Lawrence Valley and Northwest Adirondacks consists of seven short period vertical seismic field stations and one three-component broadband station. Most of the earthquakes recorded by this node occur in a northwest trending belt extending from the Adirondack Region across the St. Lawrence River into Western Quebec. The majority of earthquakes have magnitudes ranging from 2 to 4 and the foci occur at shallow depths usually less than 8 km. No major known active fault visible at the surface occurs in the area and it is believed the earthquakes are due to shallow fractures or weak zones that are ruptured due to high stresses. The reason why these quakes have a northwest trend is not clearly understood. Fault plane solutions of several earthquakes in the NW trending belt indicate the quakes are being triggered by thrust faulting along northwest trending faults, the same direction as the earthquake belt.

Thirty earthquakes have been detected in the past two years in New York State and Western Quebec. Eighteen of these earthquakes had epicenters located in New York State with four epicenters located near Dannemora, Newcomb, Bombay and Amsterdam, New York. A few of the quakes may be aftershocks of the 1944 Massena-Cornwall earthquake and the 1983 Goodnow earthquake near Newcomb, N.Y.