This is the moment mysterious glowing lights appeared in the night sky above Mexico during the most powerful earthquake to hit the country in a hundred years.
Footage shows glowing lights above what is believed to be Mexico City as fierce 8.1-magnitude tremors rattled the nation’s capital last night.
Multi-coloured flashes can be seen as buildings and lamp poles shake below during an earthquake that has so-far claimed six lives.
The lights immediately sparked speculation online, with social media users suggesting a range of explanations, including thunderstorms, a solar phenomenon and even reflection from city lights.
Video of the flashes was posted online by Twitter user L4LO, who said it was taken during the earthquake.
One possible explanation is so-called earthquake lights – rare flashes in the sky that occur during tremors.
According to National Geographic, scientists in 2014 wrote a paper suggesting such lights were caused by electrical properties of certain rocks.
The lights can sometimes take ‘many different shapes, forms, and colors,’ according to Friedemann Freund, an adjunct professor of physics at San Jose State University and a senior researcher at NASA’s Ames Research Center.
Previous theories attempting to explain the lights included the idea that the Earth’s magnetic field is disrupted by tectonic stress.
But Freund said in his paper: ‘When nature stresses certain rocks, electric charges are activated, as if you switched on a battery in the Earth’s crust.
Basalts and gabbros rocks are particularly given to the phenomenon as they have small defects in their crystals and when a seismic wave hits, electrical charges may be released.
These rocks are present in giant underground vertical structures in some areas, with the ‘dikes’ funneling charges along, according to the scientists, who added: ‘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’ creating the dramatic light shows.
It is not the first time such lights have appeared. Small flames of light were seen above a stone street seconds before the 2009 earthquake in L’Aquila, Italy.
There were also reports of a faint rainbow of light before the 1906 earthquake in San Francisco.