Scientists say three earthquakes on same date years apart is ‘coincidence’

Scientists have said that three earthquakes occurring on the same date in Mexico years and decades apart is a coincidence.

The alerts for Monday’s incoming earthquake came within the hour of the warning systems being used in a drill to commemorate the previous earthquakes on 19 September in 1985 and 2017.

In 1985, an 8.0 quake struck near the coast of the state of Guerrero, killing at least 9,500 people, according to the Associated Press. In 2017, more than 360 people died in a 7.1 earthquake and on Monday, 19 September 2022, a quake killed at least two people.

US Geological Survey seismologist Paul Earle told the AP that “this is a coincidence”.

“There’s no physical reason or statistical bias toward earthquakes in any given month in Mexico,” he added.

The seismologist told the news agency that there’s no particular season or month for major quakes anywhere in the world. But people tend to look for coincidences that appear to be a pattern.

“We knew we’d get this question as soon as it happened,” he said. “Sometimes there are just coincidences.”

Dr Earle said the quake wasn’t linked to the exercise that had occurred an hour before and also had no connection to the quake in Taiwan on Sunday.

According to Laura Velázquez, Mexico’s national Civil Defense Coordinator, the two deaths on Monday were caused by the partial collapse of buildings. Ten people were injured, nine of whom were in the state of Colima and one in the state of Michoacan.

Dozens of schools and health clinics were damaged, Ms Velázquez said on Tuesday, according to the Associated Press. In total, more than 200 buildings were damaged. Most of that damage happened in Colima and Michoacan, with around 20 buildings suffering minor damage in Mexico City.

The coincidence has led to a rise in anxiety for many.

Call centre coordinator Jorge Ornelas told the news agency that “it’s really strange, but a lot of people already don’t like that day”.

He said many start to worry about a quake as the month of September arrives.

“If we keep thinking that every September 19 it’s going to shake, it’s going to continue happening every year, because what you think is always what happens,” Mr Ornelas, 35, added.

Seismology researcher Xyoli Pérez-Campos at the National Autonomous University of Mexico’s Geophysical Institute told the AP that there’s no physical reason for significant quakes to occur on the same date.

He added that the quake on Monday was prompted by the “interaction of the Cocos plate with the North America plate,” similarly to the earthquake in 1985.

The territory of Mexico runs across parts of five plates.

“The plates break when it’s their time to break,” the researcher said. “What are they going to know about the calendar?”