Luminous Phenomena of Earthquakes: Observations and Theories

Over the past few years, different theories (piezoelectric, positive holes, friction-vaporization, exo-electron emission, tribo- or fracture electrification) have been presented for the interpretation of earthquake lights. Although these theories can interpret earthquake luminous, each suffer from particular problems. There are also ambiguities and questions about the location of the light, the number of light created in an earthquake, the relationship between light and lithology and the different light spectrum. In addition, the proposed theories could not interpret all the observed light (co-seismic and pre-seismic luminous), and it seems that more than one theory is needed to justify the lights. The relationship of the EQLs to active tectonic boundaries suggests all the earthquakes in which light has been seen are located on the active tectonic boundaries and the stress for producing lights should be at its maximum. This study shows that a new theory is needed. A theory that can, above all, explain the relation of light (spectrum and intensity) to lithology, the amount of stress, and active tectonic areas.