CAN LARGE EARTHQUAKES M > 7 IN THE ACTIVE CHARLEVOIX ZONE IN CANADA CAUSE DAMAGE IN NEW YORK STATE

On November 25, 1988, an earthquake of magnitude 6.0 occurred near the Charlevoix region 360 km north of New York State. It was the largest earthquake to occur in eastern North America in over 50 years. This earthquakes occurred outside the famous active Charlevoix and indicated that possibly the historical earthquake record of large earthquakes in the past may not be as reliable of earthquakes in the future. This earthquake, known as the Saguenay Earthquake, caused $10,000,000 damage in Canada and was felt all over eastern Canada and the northeastern United States.

An intensity survey of the Saguenay earthquake was conducted in New York State. Over 434 questionnaires were returned from as far south as Syracuse and northeast as Plattsburgh. The comments that were reported most often were: a rumbling effect with dishes and glassware rattling, walls creaking, and furniture moving. One report stated rock slides at Boonville, NY, and another felt the effect of the quake while boating. The survey also indicated cracked plaster walls, trailers rocked and glassware knocked off shelves. The intensities reported throughout New York were III and IV on the Modified Mercalli Scale with intensities IV extending northeastward along the Adirondack Highland-Lowland boundary.

Earthquake induced liquefaction features in the Charlevoix area suggest large earthquakes M > 6.5 have occurred there in the past. If we assume an earthquake of magnitude seven in the area and calculate its effect in New York State by using the formula of Atkinson, we obtain an intensity of VI in New York State. This intensity and the results of our intensity survey indicated that New York State is vulnerable to damaging effects caused by large (M > 7.0) earthquakes in the active Charlevoix zone.