Weather & Science

Mexico Quake Had 0.00075% Chance of Repetition, Expert Says

  • Math whizzes try to calculate improbability of Mexico quake
  • Earthquake happened on the same day in 1985, 2017 and 2022
Rescuers search for survivors in a flattened building in Mexico City following the earthquake in 2017.Photographer: Yuri Cortez/AFP/Getty Images
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The odds of an earthquake occurring on this day -- the same day that one toppled buildings in Mexico City in 1985 and then seemed to come back to haunt people in 2017 -- left math whizzes trying to calculate just how improbable it was.

Soon after noon, people looked up as the humming sound of an alarm reverberated across the capital and many states, a drill meant to test the readiness of earthquake warning systems. Right after 1 p.m., the shaking started. A 7.5-magnitude quake had struck.