Earthquake lights are one of the oddest geological phenomenon out there. An above ground light shown can sometimes be seen just before an earthquake occurs. Geologists were baffled for the longest time as to why this event can occur.
The newest explanation says that electrical charges are activated within the bedrock as tectonic stress builds up. The charges are released when the seismic wave hits the surrounding rock. This process causes the amazing natural light show moments before an earthquake occurs. Basalts and gabbros are most likely to have earthquake lights just prior to the earthquake.