‘On an April day in 2009, bizarre four-inch flames of light were seen hovering above a stone-paved road in the historical city center of L’Aquila, Italy. Shortly after, a cataclysmic magnitude 6.3 earthquake devastated the area reportedly leaving about 300 people dead.

At the time, these light-filled flashes were thought to be a coincidental phenomenon, but now researchers believe they had a direct correlation to the earthquake.

A new study published in Seismological Research Letters says these flashes of light rarely seen before or during earthquakes are caused by naturally occurring electrical processes in certain types of rock.

L’Aquila was one of several places to see such lights before an earthquake. Other instances include the 1906 earthquake in San Francisco, Calif., where locals witnessed a rainbowed light beam above a street right before the temblor, and the 1988 earthquake in Quebec, Canada, where people saw a purplish glowing sphere near the St. Lawrence River 11 days before the quake, according to National Geographic.

The lights can come in “many different shapes, forms, and colors,” study coauthor Friedemann Freund, an adjunct professor of physics at San Jose State University and a senior researcher at NASA’s Ames Research Center, told National Geographic. Not only are there globes of light and flickering flames, but some earthquake lights look like quick bursts of lightning coming straight out of the ground.

Past explanations for these strange colorful lights that preceded earthquakes were UFOs, birds, and planes. The phenomena is rare — it only happens in less than 0.5 percent of earthquakes — which would explain why some witnesses have claimed they were caused by aliens.’ (CNET News).