The Loch Ness monster has captivated our imaginations for decades now; the few people who claim to have captured it on film have gone down in history as an elite group lucky enough to have been in the right place at the right time, as nutjobs who believe in things that can’t possibly exist, as fame-seekers who just want attention from the media. From the first shadowy glimpse in a grainy black-and-white photo back in the ’30s, we were hooked.

While there are some who say that it can’t be out of the realm of possibility for a descendant of a water-dwelling dinosaur to have survived in the Loch, there are others who say it’s not a flesh-and-blood creature at all. One scientist believes it’s merely a trick of they eye observing the effects of an underwater earthquake on the surface.

Geologist Luigi Piccardi says that a fault line running beneath the body of water–the Great Glen fault system–is to blame for seismic activity that has, interestingly, coincided with the Nessie sightings.

“There are various effects on the surface of the water that can be related to the activity of the fault,” Piccardi said in an interview published in the Italian newspaper La Repubblica. “We know that this was a period (1920-1930) with increased activity of the fault. In reality, people have seen the effects of the earthquakes on the water.”

The fault line is reportedly 62 miles long and divides the Scottish Highlands in half. In fact, it’s said to be the reason that Loch Ness exists at all. But many who claim to have seen something in the water swear that it’s an actual living thing and not just an illusion. Last year, George Edwards–who has “hunted” Nessie for 25 years–captured a photo of something that looks like an enormous fish breaking the surface. In 2011, Marcus Atkinson said he captured something on sonar following his boat at a depth of 75 feet.