Mysterious lights appear in Mexico sky during massive earthquake | FoxNews
The quake, which registered a level of 8.4, killed dozens and was the strongest in a century, was accompanied by flashes of green and blue lights shooting throughout the night sky. According to a Google Translate version of an El Universal story, the lights are a naturally occurring electro-magnetic charge, caused by the collapse of the rocks in the ground during the earthquake.
In 2001, NASA scientist Friedmann Freud discovered that "if the stress level (between the rocks) is high, there are electronic loads that momentarily transform insulation rock into a semiconductor." Freud added that the electrical loads are not easy to measure, as they "move with impressive speed, as high as 300 meters per second."