Antonio Lira
Earthquake lights seen in Mexico City.
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Reports of “earthquake lights,” like those seen in videos taken before Friday’s 6.8-magnitude earthquake that struck Morocco, go back centuries to ancient Greece.
These explosions Bright, dancing light of different colors John Deere, a retired geophysicist who used to work for the US Geological Survey, said that this phenomenon has puzzled scientists for a long time, and there is still no consensus on its causes, but it is “certainly real.” He has co-authored several scientific papers on Earthquake Lights, or EQL.
“The visibility of EQL depends on darkness and other preference factors,” he explained in an email.
He said the recent video from Morocco shared online resembles earthquake lights captured by security cameras during the 2007 earthquake in Pisco, Peru.
Cell phone video and the widespread use of security cameras have made studying earthquake lights easier, said Juan Antonio Lira Cacho, a physics professor at the Universidad Nacional Mayor de San Marcos in Peru and the Pontifical Catholic University of Peru, who has studied the phenomenon.
“Forty years ago, it would have been impossible,” he said. “If I saw them, no one would believe what I saw.”
01:39- Source: CNN
Aerial footage shows the extent of the destruction caused by the Moroccan earthquake
Earthquake lights can take several different forms, according to a chapter on the phenomenon co-authored by Dear and published in the 2019 edition of the Encyclopedia of Solid Earth Geophysics.
Sometimes, the lights may look similar to ordinary lightning, or they may be like a bright stripe in the atmosphere similar to the aurora borealis. Other times they resemble glowing balls floating in the air. They may also look like small flames flickering or crawling along or near the ground, or like larger flames emerging from the ground.
Video taken in China shortly before the 2008 Sichuan earthquake It shows bright clouds floating in the sky.
To better understand earthquake lights, Dear and his colleagues collected information on 65 American and European earthquakes linked to reliable reports of earthquake lights dating back to the year 1600. They shared their work in Paper 2014 Published in the journal Earthquake Research Letters.
The researchers found that about 80% of the EQL cases studied were observed in earthquakes with a magnitude greater than 5.0. In most cases, this phenomenon was observed shortly before or during the earthquake, and was visible up to 600 kilometers (372.8 mi) from the epicenter.
Earthquakes, especially strong ones, are more likely to occur along or near areas where tectonic plates meet. However, a 2014 study found that the vast majority of earthquakes associated with luminous phenomena occurred within tectonic plates, rather than at their boundaries.
Furthermore, earthquake flashes were more likely to occur in or near rift valleys, places where the Earth’s crust has been torn apart – at some point in the past – creating a long depression sandwiched between two higher masses of land.
Antonio Lira
Earthquake lights seen in Guayaquil, Ecuador, shine white.
Friedman Freund, Deere’s collaborator and assistant professor at San Jose State University and former researcher at NASA Ames Research Center, has come up with one theory for earthquake lights.
Freund explained that when certain defects or inclusions in rock crystals are exposed to mechanical stress — such as during the buildup of tectonic stresses before or during a large earthquake — they instantly break down and generate electricity.
He said that rocks are an insulating material, and when subjected to mechanical stress, they become semiconductors.
He added: “Before the earthquakes, huge amounts of rock – hundreds of thousands of cubic kilometers of rock in the Earth’s crust – were under pressure, and the pressures caused grains and mineral grains to shift relative to each other.” Interview via video call.
“It’s like powering a battery, generating electrical charges that can flow from stressed rocks to unstressed rocks and through them,” he explained in a 2014 article in The Conversation. The charges travel at speeds of about 200 meters per second, he explained in a 2014 article in The Conversation.
Other theories about the causes of lights include earthquakes Static electricity from crushing rocks and the release of radon gas, among many others.
At present there is no consensus among seismologists on the mechanism that causes earthquake lights, and scientists are still trying to decipher the mysteries of these explosions.
Freund hopes that one day it may be possible to use earthquake lights, or the electrical charge they cause, to In combination with other factors, to help predict an approaching major earthquake.
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