April 20, 2002, started out like a typical Saturday morning for residents of the Northeast; or so they thought. That was until doors and mirrors started shaking, decorations began falling off walls and windows started breaking.
Hard as it was to believe, it was an earthquake registering 5.1 on the Richter scale that made upstate New Yorkers feel the earth move under their feet. The quake cracked roads and water mains and rattled homes from Maine to Maryland. Striking at 6:50 a.m. EST, its epicenter was in the town of Black Brook, 15 mil. southwest of Plattsburgh, NY, and 3.1 mi. beneath the earth’s surface. Witnesses said the shaking lasted between 15 and 30 seconds. No injuries were reported.
New York’s Gov. George E. Pataki declared states of emergency in Essex and Clinton counties later in the day saying, “We need to inspect the roads, bridges and dams to be sure none of the infrastructure was damaged.”
Several Areas Sustain Damage
At first glance it appeared the area suffered no real damage. However, a more in-depth look indicated otherwise.
An explosion in the hamlet of Jay, NY, disrupted power to approximately 3,500 residents. New York State Electric & Gas said the earthquake had triggered the explosion at a substation. Jay also sustained structural damage to several buildings. Part of the roof of the town office building collapsed and several businesses were damaged.
In Au Sable Forks, 15 mi. south of Plattsburgh, the earthquake broke off a 100-ft. (30.5 m) section from one road. Parts of at least two other roads in that area had collapsed culverts and there were several water main breaks. At least three churches serving that Adirondack village suffered damage, including collapsed chimneys, punctured roofs and cracked walls.
Some stretches of roadway pavement along Route 9 near Plattsburgh crumbled into swamps by the Au Sable River. A flood in the summer of 1998 had already weakened that road. “There were three areas of Route 9N between Keesville and Au Sable Forks with slope failure,” said Chris Neiley, regional construction engineer of the New York State Department of Transportation’s (NYSDOT) Region 7. “To repair those sections, crews have to go down to the toe of the slope, pull out the failed material and replace it with limestone.”
According to NYSDOT, a spring runs under that road in spots and when the earthquake hit the saturated mud, it shifted, fracturing about 30 ft. (9.1 m) of roadway. Officials originally believed the road might have to be shut entirely because of the possibility of more pavement giving way. Parts of several other roads collapsed near the Plattsburgh epicenter.
Repair crews were mobilized on Saturday, April 21, with work beginning on Sunday, said Neiley. Repairs were completed by Reale Construction Co., of Ticonderoga, NY, under an emergency stand-by contract.
Tremor Toll Could Be Costly
Damage from the earthquake is estimated to exceed $14 million. Officials in the locations surrounding the epicenter have called on Gov. Pataki to formally request federal disaster aid for the area. In the town of Dannemora, it is reported that 40 manhole covers — costing $5,200 apiece — were cracked and need to be replaced. A county road south of Plattsburgh could cost up to $1 million to repair and DOT is expecting to pay $300,000 to repair the cracked portion of Route 9.
A Few Facts
An earthquake is caused by a sudden slip on a fault. It occurs when plates grind and scrape against each other. Stresses in the earth’s outer layer push the sides of the fault together. Stress builds up and the rock slips suddenly, releasing energy in waves that travel through the rock to cause the shaking that is felt during an earthquake.
William Ott, a seismologist at Weston Observatory, at Boston College, said a typical earthquake of the magnitude that hit the northeast would cause cracked plaster, broken windows and minor structural damage near the epicenter.
The largest earthquake recorded in New York, according to the U.S. Geological Survey, was a 5.8 magnitude quake in 1944 that was centered in Massena about 3 mi. from the Canadian border.
