Residents of Summerville have reported sightings of a mysterious glowing light over the town's old railroad tracks. The pictured tracks, while not the "haunted" site, were studied in an effort to determine the source of the 1886 Charleston earthquake. Susan Hough via Seismological Society of AmericaIn Summerville, South Carolina, a mysterious light has been seen hovering over old railroad tracks. Legend has it, its the glow of a lantern lighting the path of a ghost searching for her decapitated husband.Now, a seismologist has offered a scientific explanation for the floating orb: earthquakes. Susan Hough at the United States Geological Survey (USGS) published her idea in a research article late last month in Seismological Research Letters.Hough was studying the areas seismology, scouring old records with references to the Summerville Light, while trying to pinpoint the source of the destructive 1886 earthquake in Charleston. Then, she read a Halloween-themed USGS newsletter on spooky science.That sparkedso to speakan idea that had been in the back of my mind, working on Charleston, that I had never really even thought too much about, says Hough in a statement from the Seismological Society of America. What about those ghost stories from Summerville?Hough suggests the towns paranormal legends actually point to earthquakes. She noticed that many of the local ghost sightings coincided with periods of seismic activity.People said their cars would shak violently. Well, thats an earthquake, Hough says to Sciences Richard Stone. They heard noises upstairs, whispers. Or doors would swing. Seismic events we may not perceive as earthquakes fit some of these accounts. And glowing orbs that would hang in the air along a former railroad track. Well, that makes you think earthquake lights.Earthquake lights are mysterious phenomena that have been observed around the world, but scientists still dont have a clear idea of what causes them. Some have proposed that seismic activity deforms minerals in the Earth, creating an electrical charge that can lead air molecules to glow. Another theory is that theyre related to the release of gases like radon or methane, which can ignite when theyre exposed to a spark of static electricity. Hough believes the railroad tracks, in particular, are the key to Summervilles ghosts.Historically, when [rail companies] replaced tracks, they didnt always haul the old track away. So, youve got heaps of steel out there. Sparks might be part of the story, Hough says to Science. And maybe the railroads are important for another reason. They may naturally follow fault lines that have carved corridors through the landscape.That could explain why so many ghost storieseven beyond Summervilleinvolve lights over railways, she adds. When you start looking around, it turns out theres any number of ghosts wandering around railroad tracks with lanterns looking for severed heads, says Hough to Jonah Chester at the Post and Courier. Theres kind of an epidemic of them.Recognizing this connection could help scientists find seismic zones that have gone unrecognized so far. Following similar ghost stories in other regions could point to areas with a low level of earthquake activity that had only been noticed through earthquake lights, per the statement.Earthquakes are an appealing explanation for these ghost stories, says Will Levandowski, a geophysicist with the consulting company Tetra Tech who was not involved in the study, to Carolyn Wilke at the New York Times.Get the latest stories in your inbox every weekday.Filed Under: American South, Chemistry, Earth Science, Earthquakes, Geology, Mysteries, New Research, Trains