So what the hell is earthquake light I hear you ask?

Well a big clue is in the name. Earthquake light is a very rare naturally occurring type of light that can be seen before, during and after an earthquake. Although scientists know the trigger very little studies have been done. This is mostly down to the rarity and the fact that nobody is sure how to predict them.
One theory is that the light is seen because of upsets in the earth's magnetic field caused by an earthquake.
So during an earthquake the magnetic field that sits between us and natural light in the sky becomes distorted, this separates the visible white light that the human eye sees into its reflective index showing all the colours that it is made up of (imagine a rainbow but shaped more like a ball).
I know what your thinking - it was dark when this happened, well a scientist would tell you that light is always around us no matter how dark things look.