Beneath the Bronx, a century-old observatory monitors Earth’s movements

Whenever the ground shakes, a small cylindrical device inside a vault 30 feet beneath Fordham University’s Bronx campus pays attention.

It’s called a seismometer, and it’s housed under a building known as the William Spain Seismic Observatory. It’s easy to stroll past the austere Gothic structure and overlook its 100-year history of observing the Earth’s rumblings.

The observatory has recorded earthquakes from all across the globe over its long existence, including the magnitude 4.8 temblor that shook New York City last April. While New York isn’t generally viewed as a hotbed of seismic activity, more occurs under the surface than meets the eye, and the observatory is part of a vast network that monitors those movements. The data it collects is forwarded to Columbia University’s Lamont-Doherty Earth Observatory and the U.S. Geological Survey, where it’s used to assess earthquake risk and remediation in large urban centers.

The observatory was named for a Fordham student who died suddenly in the 1920s, and was donated by his wealthy father. It’s the oldest of New York City’s seismic stations and can be seen as the continuation of a tradition stretching back centuries. The Jesuits who helped establish Fordham made strides in a number of scientific fields, but left such a mark on seismology in particular that it’s sometimes called “the Jesuit science.”

“The Jesuit involvement goes back to 1755,” said seismologist John Armbruster, referencing the earthquake that devastated the Portuguese capital city of Lisbon that year. Because it struck on All Saints Day in a devoutly Catholic country, the widespread damage it caused spurred fundamental philosophical and religious debates about the nature of God.

It was also the first earthquake to be scientifically studied for its effects over a wide area. Armbruster, who works at Lamont-Doherty, said the Jesuits recognized the risks earthquakes presented to their flock and sought to study and understand them, which led to the establishment of seismic observatories across the globe — and the science of seismology was born.

The intersection of religion and science is visible at the observatory. A plaque of St. Emidius, whose name is traditionally invoked for protection against earthquakes, adorns the entrance to the observatory building. It was blessed by Pope Pius XI and dates to the mid-1920s.

No Jesuit at Fordham is more synonymous with seismology than the Rev. J. Joseph Lynch, who was involved with the observatory from the 1920s to his retirement in the ‘80s. The media often sought Lynch out for his commentary and knowledge about earthquakes.

Stephen Holler, the head of Fordham’s physics department and the observatory’s current manager, described Lynch as “very impactful in the seismology field.”

“The station’s 100 years old, and [Lynch] was an integral part of it for much of its history,” Holler said. “So much so that I think it was his domain.”

Lynch had alarms in his on-campus residence, classroom and his office that would immediately alert him to any seismic events, Holler said. The early equipment’s sensitivity could sometimes lead to some mishaps, like a 1960s incident recounted to Holler by a Fordham alum.

“They stood beside the seismic station, they jumped up and down until they made enough of a disturbance that it set off the alarms,” Holler said, adding that Lynch wasn’t happy when he discovered the pranksters.

But after Lynch’s death in 1987, “there was really nobody to take over afterward,” Holler said, and the observatory entered a long period of decline until around the turn of the millennium.

“In the spring of 2001, a physics professor, Benjamin Crooker, contacted me about possibly resurrecting the seismographic stations at Fordham University that were discontinued in the late 1980s after the death of Father Lynch,” Lamont-Doherty seismologist Won-young Kim wrote in an email.

That January, hundreds of thousands of New Yorkers felt the rumble of a magnitude 2.4 earthquake centered on the Upper East Side. It didn’t cause any damage and actually provided an opportunity for the long-neglected observatory to rebuild.

“An alumnus of Fordham University inquired if the university recorded the earthquake,” Kim wrote. “After learning that the seismographic station did not work, the alumnus funded a modern seismographic station. That is when professor Ben Crooker contacted me, and together we developed a digital seismographic station with a broadband seismometer and data transfer using the internet.”

The revamped observatory began sending data in 2002, and its current seismometer shows just how far technology has come since Lynch’s time. The small cylindrical device operates using digital technology and sits atop a concrete slab in the subterranean vault, which picks up seismic waves transmitted via the bedrock.

“I think that’s probably an advantage of the advancements in the electronics,” Holler said. “You can kind of filter out that stuff that is clearly too low to be an event.”

It can accurately discern the pulse of campus and New York City life from actual seismic activity, which is more frequent here than one might expect.

“We do have quakes on the East Coast,” Holler said. “There are regular tremors, but they’re usually small and we really don’t feel them.”

The earthquakes that we do feel — such as last year’s, which Holler called “almost laughable by California standards” — tend to make headlines.

New York City has only recorded three earthquakes that exceeded the April 2024 quake’s intensity, Armbruster said, and all of them happened before the 20th century: in 1737, 1783 and 1884. But even those earthquakes are much less intense than their West Coast counterparts. Estimates for the 1884 quake, the strongest ever recorded in New York City, top out at magnitude 5.5.

Earthquakes here, however, are much more widely felt than similarly sized ones out west. That’s because the East Coast’s underlying bedrock is older, harder and denser, meaning that “the [seismic] waves will travel further before being diminished,” Holler said.

More than 180,000 people told the U.S. Geological Survey they felt the April 2024 earthquake — the largest number of responses the agency has ever received for its “Did You Feel It?” survey. Some responses even came from as far as New Hampshire – some 280 miles away from the epicenter. Fordham’s observatory “was one of the handful of seismographic stations within about 100 kilometers of the epicenter,” Kim wrote, and “provided crucial data to analyze the earthquake.”

Quakes on the East Coast aren’t caused by ongoing movements of tectonic plates as they are in California, according to a 2024 article published by the Lamont-Doherty observatory. Instead, they’re caused by ancient fault zones that sometimes jolt as they settle and readjust.

“There are fault lines still around, we’re just not moving like the West Coast is,” Holler said.

There are even fault lines under New York City, including the Dyckman Street Fault, the Mosholu Parkway Fault, the East River Fault and the 125th Street Fault. The last one is the most well-known, and is actually why the 1 train rises above ground and traverses a trestle bridge at 125th Street. Even more faults can be found in the wider metropolitan area, including the Ramapo Fault.

While the risk of a damaging earthquake striking New York City is low, it isn’t nonexistent. The city’s population density and vast stock of unreinforced brick buildings create some cause for concern, which is top of mind for city officials. According to its 2014 hazard mitigation plan, the city has more than 100,000 multifamily, unreinforced brick buildings that are three to seven stories high and were built between the mid-1800s and 1930s. Brooklyn is home to the largest number of such buildings, followed by Queens and Manhattan, according to the mitigation plan.

The city has taken some steps to address and mitigate earthquake risks. In 1995, it amended its building codes to ensure that newly constructed buildings or significant upgrades were designed to make buildings earthquake-resistant and minimize the possibility of collapse. It revised the codes in 2008 and 2014. Newer buildings are designed to sway, flex and absorb the forces generated by wind and seismic activity, as well as take the city’s unique geological conditions into account.

“Buildings and structures built on solid bedrock foundations will be less affected by the ground shaking,” Kim said. “And hence, much of Manhattan and the Bronx with abundant bedrock is relatively less affected than areas with thick sediment cover, such as Astoria, Long Island City and Queens on Long Island.”

Quakes like April 2024’s occur roughly every century or so, according to the Lamont-Doherty Earth Observatory. And based on the sizes of known faults and other calculations, scientists there estimate magnitude 6 quakes could happen every 700 years, while magnitude 7s could occur every 3,400 years.

If William Spain’s longevity is any indication, the city’s oldest seismic observatory may still be around to observe them when they come.