THE MASSENA-CORNWALL EARTHQUAKE OF SEPTEMBER 5, 1944

The Massena-Cornwall earthquake of September 5, 1944 was the largest earthquake to occur in New York State. The earthquake had a magnitude of 6.0 and was recorded on seismographs as far as Pasadena, California and Tucson, Arizona. An intensity study of the earthquake indicated a maximum intensity of VIII in the Massena Cornwall area and the earthquake was felt over an area of 448,000 km2 to Virginia and from New Brunswick to Michigan.

The epicenter was located midway between Massena and Cornwall, Canada at Massena Center. This location is about two miles south of the St. Lawrence River and southwest of the city of Cornwall, Canada. The isoseismals on intensity map are elongated in a northeast-southwest direction along the St. Lawrence River indicating the greatest intensity extends along the river and parallel to the regional strike of the Grenville structural grain.

Seismologists could not determine a definite depth since no seismic stations were in the immediate area, however estimates of depths are around 18 km. The geologic structure in the Massena area is not well known, however it is believed that crust is 36 km thick and consists of two layers, an upper layer of thickness 17.3 km and a lower layer of 18.7 km. The focus of the earthquake is probably located at the boundary between the two layers. The shallow focal depth is indicated by the rumbling and terrifying noise produced by the quake and the damaging effects being restricted to a small area.

The earthquake caused $2,000,000 damage in Massena in 1944 ($8,000,000 in today’s dollars). It destroyed 90% of the chimneys in Massena and did extensive damage to schools, churches, and other buildings. The most obvious damage was chimney and cracked brick walls.