What’s the probability of 3 quakes hitting Mexico City on the date September 19?

Autotranslation of the firts paragraph:

> Three earthquakes on September 19 in Mexico: What is the probability of happening?

> The Mexican capital has once again felt a strong tremor on the same date as in 1985 and 2017. Experts indicate probabilities between 0.000751% and 0.00000024%

Reading the title I imagined it was about three earthquakes the same day of the same year, that is very common due to aftershocks.