Last night the peaceful rest of many Mexicans was dramatically shattered by a massive 8.2 earthquake, the biggest tremor registered in this country in over a century –bigger even than the one that struck Mexico City on September 19th, 1985, which toppled dozens of buildings and claimed the lives of at least 5000 people (luckily this time damage and number of casualties was comparably small, despite the intensity of the quake).
Many lessons have been learned from that 80’s tragedy. Construction regulations have ensured that the city buildings are better equipped to withstand 8.0+ tremors. A national seismic alert system (SASMEX) provides timely warnings of earthquakes to the capital and other vulnerable cities. The government has also tried to ensure the population knows how to behave during an earthquake, by conducting periodic drills.
Which is why when civilians heard the sirens of the city’s alert system go off, many opted to leave their homes and apartment buildings and congregate on the streets, as advised by the authorities. There they manage to observe a very unusual phenomenon: Blue, white and green flashes on the fairly overcast sky. Witnesses were quick to share the bizarre spectacle through Twitter.
What the scared Mexicans –and Guatemalans– saw, were more than likely earthquake lights: a phenomenon which although well documented over the years, it still fails to have a definitive explanation. One theory suggests the illumination is the result of a release of energy when the tectonic plates collide with each other, and the stress of certain rocks cause a ‘piezo-electric’ field –the same kind of process which is used in glowing tennis shoes every time you take a step on them.
Interestingly enough, I received confirmation that similar flashes of light were also observed back in 1985. My cousin Fernando, who at the time was part of a rescue brigade in charge of delivering provisions to survivors in the neighborhood of Tlatelolco –one of the areas where the earthquake hit the hardest– told me he and his companions observed how the night sky was illuminated for a few seconds before the second major aftershock started. “It was like an electric lightning, but horizontal,” he texted me this morning.
Scientists tell us earthquake lights are more prone to occur with tremors bigger than 5 in the Richter scale. Could there be other elements behind the lights observed last night, though, like the fact we just had two major solar flares this week?
Although there’s no statistical link between an increase in solar activity and earthquakes, maybe it’s not farfetched to speculate that electromagnetic radiation from the sun could potentially induce in the appearance of lights during an earthquake.
In any case, here’s hoping Mexico doesn’t suffer from another major earthquake anytime soon. Weird lights in the sky are always exciting if you’re a UFO fan, but NOT if they are heralds of an earthly rumble…