After a 6.0 magnitude earthquake struck Napa, Calif., on Sunday morning, dozens of people contacted the KPIX 5 newsroom to report sightings of mysterious flashes of light in the sky, CBS San Francisco reported. The bizarre phenomenon was described by witnesses to appear as lightening.

From Japan to Peru, flashes of light have been reported during earthquakes around the world. A similar occurrence happened during Sunday's devastating earthquake, Friedemann Freund, a scientist with the SETI Institute in Mountain View, said, adding humorously that it wasn't UFO's or a transformer attempting to blow up the world.

"What they are, are a consequence of the stresses building up deep below the earth, seven miles like in the case of the Napa Valley earthquake," Freund told KPIX 5, calling the phenomenon "earthquake lights," the quick buildup of stress that causes an electric current to flow to the surface and burst through the earth. This typically occurs before or during an earthquake.

Several flashes were also witnessed by North Bay residents around the time that the Napa earthquake hit. Contacting Freund at the SETI Institute, they reported that there was a time lapse of one or two seconds between each one.

Meanwhile, Twitter and social networks were also buzzing with possible sightings and documentations of the strange flashes of light, according to CBS. Minutes after the quake, Keedo tweeted, "Everybody felt the earthquake but I'm the only one who saw the blue flashes in the sky??"

Anne Belden tweeted about seeing flashes of light that looked like lightning, "Saw flashes of light that looked like lightning right after earthquake, then huge green flash north of Sebastopol. #earthquake"

Although most seismologists don't believe such things to be real, Freund, who has been studying the lights for 12 years, has recently been involved with his team in looking at 65 similar occurrences around the world over the last 400 years. "There are things that we still don't understand about the earth, so why not accept unusual, exceptionally unusual phenomena taking place? And the light outburst from the ground is one of them."