What causes earthquake lights?
The most common explanation for earthquake lights is the piezoelectric effect in quartz-bearing rock. Quartz has the unique attribute of emitting electricity under pressure. Laboratory experiments have shown that this effect can produce light emissions, but they are, at least in the laboratory, of much shorter duration than reported earthquake lights. Some researchers theorize that earthquake lights are produced by seismic stresses that may generate high voltages that create small masses of ionized gas, which are then released into the air near the fault line. A second popular theory is that, during an earthquake, small pockets of trapped natural gas are released and ignited by friction. These burning balls of gas then rise in the air and create the effect of the lights. Another theory is that the pressure generated during earthquakes may cause water molecules to separate into atoms of hydrogen and oxygen, then quickly recombine back to water. In the process they theoretically could re
