www.discovermagazine.com
Susan Hough, a seismologist at the United States Geological Survey (USGS), was scouring archives for information about a 7.3-magnitude earthquake that struck Charleston, South Carolina, in 1886. Her search brought her to a bookstore where she encountered Haunted Summerville, a collection of eerie tales from a small town just north of Charleston.It was the sort of thing you stash in the back of your mind, Hough says. At first, she didnt give it much thought. But near Halloween, when the USGS drew a connection between science and the supernatural in themed emails, she recalls, that got me thinking what about those actual ghost stories?The Summerville Light was a glowing orb seen by locals throughout the 1960s on a nearby abandoned railroad. Along these tracks, legend has it, a widow still searches for the remains of her husband, a railroad worker decapitated in an accident. The bobbing light that turns orange, green, and blue, is said to be her lantern.Hough, ever the scientist, has her own explanation. She noticed the old accounts seemed consistent with a phenomenon that, although very much of this world, is hardly less mysterious: earthquake lights.Haunting Earthquake LightsThe link between ground-rumbling and strange radiance has been well-attested for thousands of years. In the mid 19th century, the Irish engineer Robert Mallet regarded as the founder of seismology compiled a list of reports dating back to 1606 B.C.E. The descriptions are diverse: luminous balls rolling along the ground or floating above it, aurora-like clouds in the sky, streaks shooting through the air, all in a range of color.Yet despite these accounts, Hough says that as recently as the 80s, when she was a graduate student, the existence of earthquake lights was still up for debate. I think most seismologists now accept that theyre real, she says. But I dont think theres a really mature accepted theory to explain them.Nevertheless, she believes the Summerville Light is a contender, as she argued in a paper published in January 2025 in the journal Seismological Research Letters. That region of South Carolina clearly has an active fault, and the sightings occurred near the epicenter of the massive 1886 quake. Whats more, several smaller temblors struck the same area in 1959 and 1960, around the time the light was first observed.There were other clues. Witnesses reported their cars shaking violently when they saw the light, which just screams earthquake, as Hough put it. The residents of creaky old buildings in town heard noises upstairs, which brings to mind shaking thats right at the threshold of perceptibility.What Causes Earthquake Lights?The evidence is only circumstantial, of course. The problem with earthquake lights, Hough says, is you cant catch them in the act. Theyre fleeting, and theyre not captured by any of the instruments we put out. Plus, the reports from Summerville ran dry decades ago.Still, she thinks there are plausible mechanisms tying the light to earthquakes. One of the most compelling comes from Yuji Enomoto, a Japanese seismologist at Shinshu University. In a paper published in July 2024, he proposed that earthquake lights could result from the chemical interactions of gases, like radon and methane, released from underground. It may be that the railroad itself plays a key role Hough bets all that steel could build up static electricity, providing the spark to ignite certain gases. That could make sense of similar lore spread far and wide across train country. There is a whole army of ghosts with lanterns wandering railroad tracks looking for severed heads, she says. You start to think, OK, is that the set of ingredients?Not everyone is convinced. John Ebel, a seismologist at Boston University and historian of East Coast earthquakes, is skeptical that whats going on in Summerville could be caused by imperceptible tremors; in his experience, earthquake lights are typically associated with major seismic events. Californias San Andreas Fault delivers mini quakes around the clock, he notes, and if even a fraction spawned luminous spheres, wed be getting reports of earthquake lights every day.That said, Ebel agrees the logic is there. Even after a century and a half, South Carolinas coastal plain is still prone to aftershocks from the 1886 quake, so it's reasonable to look for a connection between that seismicity and the lights. He just wants to see solid evidence before drawing any conclusions.A Message from BeyondHoughs work so far has pieced together historical records and theoretical research admittedly more speculative than empirical. To follow the trail further shed need to do field work, perhaps testing for gas release. But that requires funding. I imagined writing a proposal to say I basically want to go ghost-busting in Summerville, she says, laughing. I kind of balked at that idea.Whimsical as it seems, Hough hopes her foray into the occult may even prove useful. If the railroad-ghost phenomenon turns out to be a reliable sign of shallow fault activity, these stories could help scientists pinpoint potential hazard zones a notorious challenge in the eastern U.S., where earthquakes are few and far between. That, she says, is where it gets interesting and less frivolous.For now, at least, the Summerville mystery lives on. Whos to say there isnt a spectral widow wandering the tracks by moonlight, searching for her husbands head? But that, Hough adds, is outside the purview of seismology.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:Seismological Research Letters. Prevalence of Earthquake Lights Associated with Rift EnvironmentsSeismological Research Letters. Haunted Summerville: Ghostly Lights or Earthquake Lights?Cody Cottier is a contributing writer at Discover who loves exploring big questions about the universe and our home planet, the nature of consciousness, the ethical implications of science and more. He holds a bachelor's degree in journalism and media production from Washington State University.
