What's with those creepy weird blue lights accompanying the Mexico earthquake?

Last Wednesday, a 7.0 magnitude earthquake shook Acapulco and surrounding areas as far as Mexico City around 200 miles away. As people poured out of buildings, they were shocked to see blue flashes across the sky. Check out the amazing videos below. Turns out the strange phenomena don't (necessarily) mean the end of the world is nigh, but scientists do have differing opinions about what causes the freaky flares. From NPR:

Some scientists believe the eruption of light, or luminosity, is caused by the friction of rock near Earth's crust, which releases energy into the atmosphere. The flash of light is produced near the planet's surface.

[That said] USGS earthquake geologist Austin Elliott stresses not to rely on videos supposedly illustrating the EQL [earthquake lights] phenomenon.

He says most of what was seen in Mexico's skies on Tuesday night following the earthquake were power flashes from swinging wires in the electricity grid hitting other lines, trees or buildings.

"If there were visible natural electrical phenomenon going on, that would have been difficult to discern alongside the bright power flashes from the electrical grid," says Elliott[…]

National Autonomous University of Mexico seismologist Victor Manuel Cruz Atienza does believe in the phenomenon, but says last night's sky was full of a lot of electrical activity from a rainstorm.

"We can't for sure associate the earthquake with the light show we saw last night, especially given the rainstorm we were experiencing,"