Why the sky lights up before earthquakes, scientists give their explanation
2023-09-15 17:42:57
TiranaPost
"Earthquake lights", like those seen in videos captured at the moment the ground began to shake in Morocco, date back centuries to ancient Greece.
These bursts of light have long baffled scientists, and there is still no consensus on what causes them.
"However, they remain definitely real," says John Derr, a retired geophysicist who worked at the US Geological Survey. He is the co-author of several scientific papers on earthquake lights, or EQL.
"Seeing EQL depends on darkness and other favorable factors," he explained.
Ai tha se videoja e fundit nga Maroku e shpërndarë në internet ngjante me dritat e tërmetit të kapura në kamerat e sigurisë gjatë një tërmeti të vitit 2007 në Pisco, Peru.
Juan Antonio Lira Cacho, profesor i fizikës në Universidad Nacional Mayor de San Marcos në Peru dhe Universitetin Katolik Papnor të Perusë, i cili ka studiuar fenomenin, thotë se përdorimi i gjerë i kamerave të sigurisë e ka bërë më të lehtë studimin e dritave të tërmetit.
“Dyzet vjet më parë, ishte e pamundur,” tha ai. “Nëse do t’i shihje, askush nuk do ta besonte atë që kishe parë.”
Dritat e tërmetit mund të marrin disa forma të ndryshme. Ndonjëherë ato mund të duken të ngjashme me vetëtimat e zakonshme, ose mund të jenë si një brez i ndritshëm në atmosferë i ngjashëm me aurorën polare.
Researchers have discovered that about 80% of such phenomena studied occurred in earthquakes with a magnitude greater than 5.0.
In most cases, the phenomenon was observed shortly before or during the seismic event and was visible up to 600 kilometers from the epicenter of the earthquake.
Possible causes of earthquake lights
Derr's associate Friedemann Freund has come up with a theory about earthquake lights.
He explains that when certain impurities in the crystals in rocks are put under mechanical stress, such as during the uplift of tectonic plates before or during a major earthquake, they immediately rupture and produce electricity.
The rock is a type of insulator that, when mechanically stressed, becomes a semiconductor, he said.
