Plattsburgh, NY Earthquake

First Posting | Summary
Posting Date: April 21, 2002, 8:00:00 AM

A moderate earthquake struck the northeastern United States at 6:50 a.m. EDT, April 20, 2002. Assigned a preliminary magnitude of 5.1 by the United States Geological Survey (USGS), the quake occurred in northern New York, about 15 miles southwest of Plattsburgh. According to the USGS, its effects were felt as far away as Cleveland, Ohio and Baltimore, Maryland. Dr. Mohammad Yazd, Director of Earthquake Research and Modeling at AIR, visited the area shortly after the event was reported by the USGS and observed the towns of Plattsburgh, Peru, and Keesville. Damage in general was light and scattered. A bridge outside of Plattsburgh on Rt. 22 showed signs of slight damage and had been closed by the New York highway department for inspection. Minor road damage was observed outside of Keesville. There have been a few reports of cracks to buildings or expansion of pre-existing cracks on driveways and sidewalks in the area. While earthquakes in the northeast are not uncommon, Saturday’s was unusually strong for the area. This is an intraplate region and the sources of seismicity here are not well understood. Seismic waves attenuate slowly due to the underlying geology, explaining why the quake was felt over such a large area. The last earthquake of similar size to occur in the region was a magnitude 5.1 event that struck the Blue Mountain Lake area of New York in 1983. The largest recorded earthquake in New York was a magnitude 5.8 quake that occurred in Massena in 1944. There is still uncertainty as to the true parameters of this event. The magnitude itself is subject to revision as data from other seismic stations become available. Nevertheless, the AIR earthquake team has run scenarios based on the currently available information. Results indicate that insured losses will be minimal. However, the fact that damage did occur from this low magnitude event indicates that it would not take a very large magnitude earthquake to cause significant damage in the northeast.

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Posting Date: April 21, 2002, 8:00:00 AM