Earthquake lights – a glow that appears in the sky before seismic tremors, similar to those seen by the inhabitants of Turkish Hatay on Monday, February 20, were modeled by Russian scientists from the Institute of Geosphere Dynamics of the Russian Academy of Sciences. The correspondent of “MK” talked about the experiment with the leading researcher, candidate of physical and mathematical sciences of the IDG RAS Tatyana Loseva.The bluish flashes that preceded a new devastating 6.6-magnitude earthquake in the Turkish province of Hatay puzzled many. The phenomenon was not like either ordinary or ball lightning. Except that it looked a bit like aurora borealis. But where can it come from in the Mediterranean?
In order not to produce unnecessary rumors, the Turkish authorities on February 21 issued a statement explaining the nature of the blue glow. The communications agency said it was related to the energy generated during an earthquake. “If a shift begins at the fault site, the stored energy is released. This leads, on the one hand, to shocks, and on the other hand, to a bright, but short-term glow in the atmosphere, which can reach a height of 200 meters above the ground. The report also says that the latter effect may not be observed with every earthquake, but only when several conditions are met for this.
– Unfortunately, the representatives of the Turkish government did not tell us what the conditions should have been before the “mysterious” outbreaks. Can you reveal their secret?
– Of course, not all earthquakes are accompanied by glows similar to the Turkish one that occurred on February 20 in Hatay. It happens that they appear in the form of lightning, balls hovering over the area. Scientists from many countries have long paid attention to them. But, since these phenomena occur quite rarely, there is still no classification of them as such.
However, based on the data of our Russian study, we can say something, at least make assumptions about the mechanism of their occurrence. Our institute modeled this effect. Based on the glow that appeared in the sky before the earthquake in the Japanese city of Kobe in 1995. When I saw this over Khatai and compared the parameters with the Japanese seismic event, I realized that they are very similar.
– What are these parameters?
– This is a relatively small depth of the earthquake epicenter, up to 20 kilometers (in Japan it was 17.2 km, in Hatai – 16.7 km), not far from the sea coast. Even the relief of the coastline turned out to be very similar.
– Describe, please, the mechanism of formation of a light patch in the sky.
– In a nutshell, this can be expressed by an interconnected chain of reactions: during the movement of the fault walls in the epicenter of the earthquake, currents are generated – these currents generate electromagnetic fields – electromagnetic fields lead to a glow in the sky.
Tell us about your modeling. Did you take parameters for it from the works of Japanese researchers?
“We started doing this almost 10 years after the earthquake. By that time, there were enough data on the length and depth of the fault, on the features of the core and the magnitude of the currents. Then I wrote a computer code that defined the 3D configuration of the fault, the magnitude of the current, how it changed in space and time.
According to the work of Japanese scientists, traces of strong heating (about 1200 Kelvin) and even melting were found in the fault when drilling on Awaji Island (it is located near Kobe). In accordance with this fact, the magnitude of the current in the fault was chosen.
– And what mechanisms give rise to these currents?
– It’s hard to say – there can be many answers. We assumed that the electricity there was caused by the friction of one wall of the fault against another.
It turns out that the friction and ultimately leads to the glow?
– It turns out that way. If our fields penetrate the atmosphere, huge hemispheres with a radius of half a kilometer are formed.
According to our mathematical model, the fields above the surface are very strong, a thousand times higher than the background values - tens of kilovolts per meter compared to 100-200 volts per meter in good weather. Even under a thundercloud, the electric field is smaller – only 4 kilovolts per meter. In such a field, droplets of sea water sprayed into the atmosphere could also contribute to the appearance of the glow.
It must be said that our model gave results on the value of electric and magnetic fields close to the results of observations in Japan.
– Are you going to carry out a similar numerical simulation of the Turkish earthquake?
– Yes, we have such a desire. Despite the fact that we published our first article in the Journal of the European Geophysical Union in 2005, it still has not lost its relevance, it is often referred to, we are asked to continue modeling new earthquakes.
– By the way, you said that the fires of earthquakes can be in the form of lightning and in the form of luminous balls. On what it depends, did not find out?
– There are many assumptions: the initiation of lightning discharges in the case of an increase in the electric field on its local amplifiers (drops, blades of grass, etc.), changes in the properties of water under the influence of electric and magnetic fields, the occurrence of intra-cloud lightning discharges, the glow of which looks like a diffuse glow, etc. .d. Elucidation of the mechanism requires further both theoretical and experimental research.