Disassembling the myth: why September 19 is not a "earthquake magnet" as believed

Mexico, a country where tremors do not respect dates

The National Seismological Service records 74 earthquakes of magnitude 7.0 or greater since 1900, of which seven occurred at least twice on the same date, which shows that on September 19 it is not special or unique for the repetition of earthquakes of great magnitude.

For example, on April 15, 1907 and April 15, 1941, earthquakes of 7.6 degrees were recorded. This date is not associated with strong tremors because it is not part of our recent collective memory and belongs to another era in the history of Mexico.

Other dates with relevant earthquakes are October 24, with at least four tremors of 6.6 to 7.1 degrees, and on June 7, with five earthquakes of 6.5 to 7.6 degrees, which reinforces that these are statistical coincidences and not “special” days.

“Three earthquakes have occurred on December 10, the most recent in 2011 (almost 14 years ago). We tend to remember the latter mainly; that’s why people think: ‘This is weird, there is something that is being hidden from us. But, why September 19?’ Statistically, it is even normal. “

Something common for a seismic country

Dr. Quintanar points out that there is no line of research that specifically studies the earthquakes of September 19; The day is no different from other dates with repetition of tremors, although statistical analysis is performed to better understand phenomena.

“If this happened in a country that is not seismic, it would give us more what to think. But in a seismic country, where so many earthquakes occur, I believe that this is, to some extent, normal,” he says, attributing the fear to date to a souvenir bias and a statistical coincidence.

Another relevant point is that the three strong earthquakes of September 19 did not share epicenters, which explains the coincidence as a statistical phenomenon. The 2022 earthquake (7.7 degrees) had greater intensity in Coalcomán, Michoacán; The 2017 (7.1 degrees) originated in Chiautla de Tapia, Puebla, and is more remembered for damage to Mexico City, due to its proximity to the capital.

The 1985 earthquake, despite happening relatively farther, in the sight, Michoacán, reached 8.1 degrees and devastated the city, which then lacked infrastructure, alarms and prevention protocols. The intensity and distance of the epicenter influence how earthquakes are perceived and reinforce the perception of statistical coincidences.

Artificial intelligence and earthquake detection

Dr. Quintanar explains that artificial intelligence is currently used to identify small earthquakes that are not noticeable to the population or visible in conventional records.

“Artificial intelligence has been used precisely to find more earthquakes of smaller magnitudes of similar characteristics, that is, that they come from the same place and that otherwise they would not be detectable or much less reportable by the national seismological service,” he says.

Thanks to this technology, more replicas of the normally reported are detected, in addition to the so -called mycrosism, which allows to better understand seismic activity and strengthen prevention and response models. Quintanar clarifies that earthquakes cannot yet predict, although new applications could arise in the future.

Prevention and message to the population

The specialist emphasizes that there is no “fateful day” for earthquakes and that attention must focus on prevention. “More than worrying about September 19, the important thing is to deal with the necessary actions, because it does not affect your home and especially your physical integrity,” he says.

It also underlines the importance of following the drills, civil protection indications and reviewing homes to repair structural damage: “If we build well and follow the regulations, even if a very large earthquake occurs, our house will resist.” It warns about the risks of inadequate modifications in buildings, which have caused collapses in recent earthquakes.

In summary, beyond the symbolic load of September 19, the fundamental thing is to bet on prevention. As Dr. Quintanar emphasizes, citizen preparation and consciousness are the best defense against any earthquake.