After the earthquake in Turkey some presumed telluric or seismic lights have been sighted. But how are they formed? Here are the two main theories.
In the last few hours there has been a lot of talk about telluric lights or seismic lights, that is, that luminous optical phenomenon that can be visible during violent earthquakes. After the 7.9 shock recorded yesterday in Turkey , in fact, many people immortalized the formation of alleged seismic lights in different areas of the country on their smartphones.
At the moment, in reality, it is not yet possible to confirm whether those were actually telluric lights, also because there is not yet a model capable of explaining with certainty how they form. But let's see what are the main theories formulated by the scientific community.
What are telluric lights?
Also called EQL ( EarthQuake Lights ), telluric lights are flashes, globular lights, diffuse clouds and flashes similar to those of a storm but more lasting, with colors that vary greatly: generally they are white and blue lights, but there are cases in which they take on shades of red and green . Although they have been observed since ancient times (the first text about it can be traced back to 2 thousand years ago, " Historia Naturalis” by Pliny the Elder), the origin of telluric lights is not yet certain: this phenomenon is still being studied and researchers have various theories – not to mention the fact that some of the lights that are observed during an earthquake are not necessarily related to this phenomenon. A famous case is that of the earthquake in Mexico in 2021 when it was discovered that the blue lights observed were not telluric but simple transformers that exploded.
Theories on the formation of telluric lights
The National Institute of Geophysics and Volcanology (INGV) at the moment confirms that there are only hypotheses about it, that is, we cannot give an explanation with certainty. However we can identify two theories that seem to have more relevance than others.
Electric fields generated by quartz
The first theory, the historical one, relates the creation of seismic lights to intense electric fields that are generated inside rocks containing quartz: this mineral is piezoelectric, therefore it can become electrically charged if subjected to pressures - such as those that can occur in rock during an earthquake. This accumulation of charge, in theory, could in turn give rise to small lightning bolts and bright discharges.
Ionization of oxygen
Let's move on to the second theory. Some recent models suggest that the generation of seismic lights may involve the ionization of the oxygen contained in some types of rocks (such as dolomite or rhyolite) as a result of tectonic stresses before and during an earthquake. The ions would be able to pass through layers of rock, even through the fractures of the rock itself, and once they reach the surface, in contact with the atmosphere, they could even ionize small volumes of air, transforming them into light-emitting plasma packets.
Obviously it is a very complex phenomenon to study. An attempt is made to replicate the dynamics in the laboratory to be able to isolate it from the meteorological factor and try to solve the problem of the reliability and credibility of the witnesses (many say that the telluric lights occur from the bottom upwards), but the road is still long and winding. The fact is that research is the only weapon we have to weaken the question marks associated with natural phenomena.
