Similar flashes of light have been reported in earthquakes around the world, from Japan to Peru.

Friedemann Freund, a scientist with the SETI Institute in Mountain View, said the same thing happened during Sunday morning's earthquake. And it wasn't a transformer blowing up or UFOs.

"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.