Mysterious green and blue flashes have been witnessed in Mexico City after it was rocked by a magnitude 8.2 earthquake.

The powerful quake triggered a tsunami warning for at least eight countries and people fled into the streets.

Mexico earthquake video reveals terrifying sound as it struck capital city

One person took a video of the earthquake light phenomenon which often happens after an earthquake strikes.

Little is known about why they occur and some believe it may be as a result of power supplies being hit while others claim that they have been reported for thousands of years.

Seismologist Stephen Hicks said: ‘Earthquake lights have never been proven. Simpler explanation is small explosions in electric generators and power systems.

The lights are similar to auroras and can sometimes continue for several minutes after or before the quake.

For example in 1975, the mystery lights appeared during and immediately after the main shock in the Kalapana earthquake in Hawaii.

They come in many colours and forms and people have reported seeing them for hundreds of years but only recently have scientists come a little closer to establishing why they appear.

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Why do they occur?

One hypothesis is that the generation of earthquake rocks ‘involves the ionisation of oxygen to oxygen anions by breaking of peroxy bonds in some types of rocks by the high stress before and during an earthquak’, according to a wikipedia page on the subject.

‘After the ionisation, the ions travel up through the cracks in the rocks. Once they reach the atmosphere these ions can ionise pockets of air, forming plasma that emits light.’

Another is that the lights are caused by the result of two layers of the same material rubbing against each other creating voltage.

According to Professor Troy Shinbrot of Rutgers University, who carried out a lab experiment with different types of grains to mimic the crust of the earth, when the layers crack, voltage discharges into the air which then electrifies the air and creates a bright electrical light when it does so.

MORE: Mexico earthquake video reveals terrifying sound as it struck capital city

Mexico was rocked by its most powerful earthquake in 32 years, which sparked panic and triggered a 2.3ft Tsunami.

Officials said that it was the strongest quake to hit the capital since the 1985 tremor that killed thousands and flattened a large party of Mexico City.

Tsunami warning as magnitude 8 earthquake rocks Mexico

The earthquake struck around 600 miles away from Mexico City and there were warnings for further waves hitting Mexico, Guatemala, El Salvador, Costa Rica, Nicaragua, Panama, Honduras, Ecuador.

The risk for Hawaii, Guam and other Pacific islands is still being assessed.

Footage emerged from the aftermath shows windows broken and buildings in darkness after the power went out in several major neighbourhoods of the capital.

The cornice of a hotel collapsed in the southern tourist city of Oaxaca, a witness said.

People in the capital, one of the world’s largest cities, ran out into the streets in pyjamas and alarms sounded after the quake struck just before midnight, a Reuters witness said.

Helicopters hovered overhead a few minutes later, apparently looking for damage to buildings in the city built on a spongy, drained lake bed.

In one central neighbourhood, dozens of people stood outside after the quake, some wrapped in blankets against the cool night air.

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Liliana Villa, 35, was in her apartment when the earthquake struck and she fled to the street in her pyjamas. She said: ‘It felt horrible, and I thought, ‘this is going to fall’.’

The epicentre was 123 km (76 miles) southwest of the town of Pijijiapan, at a revised depth of 43 miles.

USGS reported several aftershocks, all greater than 5 magnitude.

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