Morris County Earthquake Shakes Residents, Spares Property

Tuesday February 03, 2009, 6:50 PM
Many who heard a boom and felt the ground shake thought their furnace had blown up. Others feared a truck or plane had crashed. Still others surmised there had been an explosion at Picatinny Arsenal, an Army base in Morris County that tests weapons.

The mystery was solved quickly. The U.S. Geological Survey said the tremendous concussion that rattled windows, shuddered walls and appeared to echo throughout northern New Jersey Monday night was an earthquake with a magnitude of 3.0. That's considered minor, but larger than what typically rocks the state, according to the USGS.

TALES FROM THE MORRIS COUNTY QUAKE
U.S. Geological Survey

The quake occurred at 10:34 p.m., and the epicenter was about five miles north-northwest of Morristown, near Victory Gardens, said John Bellini a geophysicist with the USGS. Residents from Parsippany to Hackettstown to Bernardsville reported feeling something, according to the USGS, which collects responses at its website: earthquake.usgs.gov. But those in Dover, Wharton, Denville, Randolph, Mine Hill and the Rockaways in Morris County were the most rattled. Kevin Meyer said his house in Rockaway Township felt "like a plate on a tablecloth and somebody tried to pull the tablecloth.

"The whole house went up, and there was a loud boom," he said. "Literally, it felt like a wave of energy passed under the house. It was pretty strong. At first I wasn't sure I was awake."

Won-Young Kim, a senior scientist with the Lamont-Doherty Earth Observatory at Columbia University, got a call from State Police Monday night at 10:40 to confirm an earthquake had occurred in North Jersey. He quickly checked the reports that come in from about 40 seismic stations in the Northeast and detected a quake with a 3.0 intensity that was focused about two miles underground.

"For New Jersey or the Northeast, a 3.0 is fairly big," Kim said today. "But in California, it would be nothing, just a small event," he laughed. Kim said an average depth of a quake would be five or six miles. The shallowness of Monday night's event resulted in more shaking, causing more people to feel it, he said. If it had been focused deeper underground, it could have gone almost unnoticed, he said.

Police in several towns said there were no reports of damage or injuries, but hundreds of nervous and curious residents called asking what had happened. Randolph police alone received about 500 calls, Lt. Donald Smith said. Dover police said they had two staff members taking calls continuously for more than a half-hour.

The sound many reported hearing -- akin to an explosion or large crash -- is not uncommon, said Alexander Gates, geology professor and chair of the Earth and Environmental Sciences Department at Rutgers-Newark. "When the fracture first goes, it can make a lot of noise," he said. "If it's close to the surface, it's the sound of the rocks breaking."

In several towns, residents went outside to talk to neighbors about what they heard and felt. Many said they thought the sound and shaking -- which lasted between five and 10 seconds -- may have been an explosion at Picatinny, an Army base in Rockaway Township that tests weapons. A base spokesman said the sound didn't come from activity on post. Others feared a horrific accident.

"My first thought was a plane crash close to us and the plane exploded," said Ana Navarro of Randolph, who had just returned from the airport when she heard the sound. "I think no one in a million years would have guessed earthquake."

Actually, earthquakes may occur a few times a year in New Jersey. "We might get a year with none. We might get two to three a year," Gates said. "Most are so small people don't even notice them." They can happen across the state, but are more common in the Highlands region in the state's northwest corner, where this one occurred, Gates said. That's because there are more active faults -- or fractures in the earth -- in that area.

"The rocks in the Highlands are more brittle, and once they break, it's easier to break again," Gates said. The last earthquake reported in the state, with a magnitude of 2.1, happened in Hunterdon County in July. The largest one since 1974 was a magnitude 4.0 on Oct. 19, 1985.

The last serious earthquake in New Jersey -- with a magnitude of 5.5 -- happened in 1884 off of Sandy Hook, Gates said. That quake toppled church steeples and yanked homes from their foundations, he said. Scientists believe a 5.5-magnitude earthquake could happen every 120 years and a 7.0-magnitude quake every 3,400 years, Gates said. "Right now is when we should hit a five, we're in the range for that," he said. "It could come tomorrow, it could come 100 years from now. You don't know."