Light phenomena in the sky before earthquakes: scientists are trying to solve the mystery of flares
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Scientists are trying to solve the mystery of a strange light phenomenon that can be observed before earthquakes. We are talking about the so-called earthquake lights, which were captured on video before the recent earthquake in Morocco, CNN reports. Data on the phenomenon have been known since ancient Greece. “These flashes of bright light of various colors have long puzzled scientists, and there is still no consensus on their cause, but they are definitely real,” said John Derr, a retired geophysicist who formerly worked for the US Geological Survey. He has co-authored several scientific papers on earthquake lights, or EQL. “You can see EQL depending on the darkness and other favorable factors,” he explained. According to a scientist, a recent video from Morocco released online looks like earthquake lights captured by security cameras during the 2007 earthquake in Pisco, Peru. Juan Antonio Lira Cacho, a professor of physics at Universidad Nacional Mayor de San Marcos and Pontifical Catholic University of Peru who has studied the phenomenon, said cellphone video and the widespread use of security cameras have made it easier to study earthquake lights. “Forty years ago, this was impossible. If you saw them, no one would believe you,” he said. What is known about earthquake lights Earthquake lights take many forms. Sometimes the lights can look like ordinary lightning, or a glowing streak in the atmosphere similar to the aurora borealis. Sometimes they resemble balls that glow and float in the air. They may also appear as small flames flickering or creeping along or near the ground, or as larger flames erupting from the ground. The video, taken in China shortly before the 2008 Sichuan earthquake, shows glowing clouds floating in the sky. To better understand earthquake lights, Derr and his colleagues compiled information on 65 American and European earthquakes associated with reliable reports of earthquake lights. The researchers found that about 80% of EQL cases studied occurred during earthquakes with a magnitude greater than 5.0. In most cases, this phenomenon was observed shortly before or during the seismic event, and it was visible at a distance of 600 kilometers from the epicenter of the earthquake. Possible Causes of Earthquake Lights Friedemann Freund, a Derr collaborator, adjunct professor at San Jose State University, and a former NASA researcher, has put forth one theory for earthquake lights. Freund explained that when certain defects or impurities in rock crystals are subjected to mechanical stress – such as during a severe earthquake – they instantly break apart and generate electricity. According to him, a stone is an insulator that becomes a semiconductor under mechanical stress. “It’s like turning on a battery, generating electrical charges that can flow from stressed rocks to and through unstressed rocks. The charges travel fast, up to about 200 meters per second,” he explained in an article for The Conversation in 2014. According to another theory, the fires of earthquakes are caused by static electricity, which arises as a result of the destruction of rocks. Currently, there is no consensus among seismologists about the mechanism that causes the phenomenon, and scientists are still trying to unravel the mysteries of these outbreaks. Freund hopes that one day it will be possible to use earthquake lights, or the electrical charge that causes them, in combination with other factors to help predict when a major earthquake is coming. Read also: Is Ukraine at risk of earthquakes, as in Turkey? Seismologists answer
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