PALISADES – Scientists at Columbia University’s Lamont-Doherty Earth Observatory are warning that the Indian Point nuclear power plant in Buchanan is built atop the intersection of two active seismic faults that make it vulnerable to earthquakes.
Lamont researcher Lynn R. Sykes said data in a new study show that large quakes are less frequent around New York than in other parts of the country, but the risk is high because the area is densely populated and contains vital and expensive infrastructure, including Indian Point.
Magnitude 5 earthquakes – strong enough to cause damage -and larger have occurred in the region once every century or so, Sykes said.
The last quake that strong took place in 1884 somewhere between Brooklyn and Sandy Hook, N.J., toppling chimneys across the city and in New Jersey, and panicking bathers at Coney Island, according to accounts.
“We should certainly expect an event of that magnitude sometime in the future,” Sykes said. “When that sometime is is the big question.”
He estimates that a magnitude 6 earthquake could occur in the area once every 670 years and a magnitude 7 every 3,400 years. It is not clear when or if earthquakes that powerful have ever rocked the area.
An earthquake that strong in the metro New York area could cause damage estimated at $39 billion to $197 billion.
In a study published in this month’s issue of the Bulletin of the Seismological Society of America, Sykes and other Lamont scientists studied all 383 known earthquakes from 1677 to 2007 in a 15,000-square-mile area around New York City. The researchers say magnitude 5 quakes occurred in 1737, 1783 and 1884.
Scientists looked at the Ramapo seismic zone, which runs from eastern Pennsylvania to the mid-Hudson Valley and passes within a mile of Indian Point.
The new research shows that the system is not so much a single fracture as a braid of smaller ones, where quakes emanate from a set of faults.
East and south of the Ramapo zone is a set of nearly parallel northwest-southeast faults that researchers now think could be a more significant hazard. The Ramapo zone also includes the Dobbs Ferry fault, which generated a magnitude 4.1 shock in 1985.
James Steets, spokesman for Entergy Nuclear, owner of Indian Point, said the company has long known about a possible earthquake risk and has taken steps to prepare for it.
“There is a risk, but it’s really quite small,” Steets said.
The nuclear power plant meets all earthquake-related regulations, he said.
“If a responsible agency decided that the standards needed to be changed or improved, we will meet those standards, too,” Steets said.
Indian Point foes have long maintained that the area’s only nuclear power plant is located in an earthquake-prone area – making it all the more risky to operate.
Earthquake risk is already an issue as Entergy applies to relicense two Indian Point nuclear reactors.
The license for Indian Point 2 expires in 2013, and the license for its sister reactor, Indian Point 3, will expire in 2015.
Under current regulations, the Nuclear Regulatory Commission does not include factors such as the risk of earthquakes or terrorism when it considers a licensing application.
Phillip Musegaas, policy director for Riverkeeper, a Tarrytown-based environmental group that has long opposed Indian Point, said the earthquake risk should be considered as part of the relicensing application – especially in light of the Lamont findings.
“It’s common sense that if the science has changed, we should re-examine the assumptions about safety,” he said.
Attorney General Andrew Cuomo also has asked the NRC to consider the risk of earthquakes as it decides whether Indian Point is safe enough to continue operating.
A special board of the NRC announced this month that it would entertain debate on 15 of the 154 separate challenges to the nuclear plant’s application to keep making electricity in Buchanan until 2035.
Earthquake risk won’t be one of them, said Neil Sheehan, a spokesman for the agency.
Seismic activity is an issue when a plant is first designed, he said.
“It’s not an issue we revisit when the plant comes in for relicensing unless new and significant information is made available,” Sheehan said.
The commission is aware of the Lamont study, but has not yet had time to read it, he said.
Residents who have long fought to close Indian Point said the new Lamont study is all the more reason to shut the plant down.
“Earthquake risk should be a huge focus of the relicensing process,” said Maureen Ritter, an Airmont resident and member of the Indian Point Safe Energy Coalition, an organization composed of numerous groups opposed to the nuclear power plant. “Anything less is completely irresponsible.”
Reach Jane Lerner at email@example.com or 845-578-2458.