Mysterious 'Earthquake Lights' Appear on New Zealand Sky
Mysterious green and blue lights flared across the night sky as an earthquake shook New Zealand.
On Sunday, New Zealand was rocked by a magnitude-7.8 earthquake. The shock was amplified after flashes of light appeared on the sky "during the peak" of the quake. Videos of the event were posted by onlookers.
"The lights happened right on the peak of the shaking ... [There were] of colors mainly green and blue and white, but a bit of yellow and other color was there too," Zachary Bell, one of those who posted a footage told ABC News Australia.
Mother Nature Network said the lights could not possibly come from lightning because there were no storms in the area at the time.
Meanwhile, the report added that lights flashing during earthquakes date back thousands of years, with similar accounts also emerging after the Christchurch earthquake in 2011 and in China 30 minutes before the Sichuan quake in 2008.
"Earthquake lights" is a phenomenon that has not been properly understood. Experts who attempted to explain it said the lights are caused by electrical properties of certain rocks in specific settings.
Friedemann Freund, an adjunct professor of physics at San Jose State University and a senior researcher at NASA's Ames Research Center published a paper explaining the phenomenon.
"When nature stresses certain rocks, electric charges are activated, as if you switched on a battery in the Earth's crust," Freund told National Geographic.
"The charges can combine and form a kind of plasma-like state, which can travel at very high velocities and burst out at the surface to make electric discharges in the air," Freund added. Those discharges are what make the colorful light shows.
Common forms of these earthquake lightning includes "ball lightning" which floats in the air and those that can stretch up to 200 meters high.