“No way!” and “Ah shit, here we go again …” were among the reactions on social media to Monday’s powerful earthquake, the third in fewer than 40 years to afflict Mexico on September 19.

A 7.7 magnitude temblor with an epicenter just over 60 kilometers south of Coalcomán, Michoacán, rocked central Mexico at 1:05 p.m. Central Time, less than an hour after the simulacro nacional, or national earthquake drill, began.

It was the second time in just five years that a large quake occurred shortly after the drill, after the same thing happened in 2017.

The drill is held annually on September 19 because the worst earthquake in recent Mexican history occurred on that date in 1985, causing widespread damage and claiming thousands of lives in the capital. The drill held Monday coincidentally assumed an epicenter in Michoacán.

Fortunately, Monday’s quake wasn’t anywhere near as destructive as those in 1985 and 2017, although at least two people were killed.

“The admiral José Rafael Ojeda Durán, navy minister, informed me that a person died due to the collapse of a wall in a shopping center in Manzanillo, Colima,” President López Obrador said on Twitter Monday afternoon.

Colima Civil Protection authorities reported a second fatality at the same shopping center later on Monday.

Mexico City Mayor Claudia Sheinbaum reported “saldo blanco” or a clean slate in the capital in terms of major damage, although the newspaper El Universal said some buildings had been cordoned off due to cracks and other structural defects. In addition,  Mexico City International Airport reported some minor damage, including broken windows and “detachment of finishings such as plaster and paint from some walls.”

Michoacán Governor Alfredo Ramírez Bedolla said in a video message there were “material damages,” but no lives lost in that state. Homes, hospitals, schools and highways sustained damage, according to authorities and reports. Among the worst affected municipalities were Coalcomán, Aquila and Coahuayana. Damage to buildings was also reported in the neighboring state of Colima.

As politicians took to social media to report on the quake, so too did large numbers of everyday citizens. Some posted videos showing just how powerful the temblor was.

En Jalisco nunca había visto un Sismo de esta magnitud, en mis 33 años años de vida. Literal se movió todo. pic.twitter.com/UDLM0lWNi0

— Jorge Garcia Orozco (@jorgegogdl) September 19, 2022

“In Jalisco I had never seen an earthquake of this magnitude in my 33 years of life. Everything literally moved,” tweeted Guadalajara-based academic Jorge García Orozco above a video of vehicles rocking violently.

Other videos showed buildings, electrical posts, traffic lights and public monuments swaying in different parts of the country, including Michoacán and Mexico City.

Several Mexico-based foreign journalists also tweeted about the quake. “No f***ing way. On the anniversary of Mexico City’s two mega earthquakes it just rumbled again,” wrote Ioan Grillo, a noted drug war journalist.

“Unbelievable that Mexico has been hit by a third earthquake on 19 September today,” said Duncan Tucker, a British journalist and Amnesty International’s Regional Media Manager for the Americas.

Andy Altman-Ohr, a Mexico News Daily writer who was in central Mexico City when the quake hit, described the seismic event as a “long low temblor.”

“… Our legs felt like jelly and signs were swinging, and the wave motion underfoot continued for 20 seconds in the middle of the street,” he said in a message to colleagues.

Celeste Labedz, a Canada-based environmental seismologist, described the occurrence of the quake on the same day as previous temblors as an “astounding coincidence.”

“Today in astounding coincidences: Mexico had a nationwide earthquake safety drill today to mark the anniversary of the Sept 19, 2017 M 7.1 quake and the Sept 19, 1985 M 8.0 quake. An hour after the drill, a M 7.6 quake struck,” she tweeted above a link to Mexico News Daily‘s earthquake drill story.

Note: ‘astounding’ in a human perspective doesn’t mean anything geophysically strange is up! Mexico is no stranger to large quakes (especially on the subduction zone), and the probability of date coincidences can be surprising, as in the Birthday Problem,” Labedz added, referring to probability theory.  

For his part, National Autonomous University physicist José Luis Mateos, said that the probability of having three large-magnitude earthquakes on the same day was one in 133,225, or 0.00075%.

In a statement issued early Monday before the earthquake, the National Disaster Prevention Center (Cenapred) noted that there had been five major earthquakes in September since 1985, but stressed that it was coincidence they all occurred in the ninth month of the year.

“In collective thought there is a belief that September is the earthquake month, mainly due to those that occurred in 1985, 2017 and 2021. However, this is a coincidence,” Cenapred said.

Jan-Albert Hootsen, a Dutch journalist and Mexico representative of the Committee to Protect journalists, expressed support for that view.

“No, there is no such thing as an ‘earthquake machine’ someone turns on and aims at Mexico every September 19. As statistically unlikely as it is, it IS a coincidence that three quakes hit Mexico on September 19 [in] the last 30 years. Plate tectonics don’t have an agenda,” he wrote on Twitter.

“… Mexico’s Pacific coast is littered with fault lines. There are earthquakes every single day (also every 19/9), but we don’t feel the vast majority of them. The earth’s crust is unpredictable. Sometimes it does very unlikely things.”

In the wake of the powerful 7.7 magnitude earthquake – which triggered a tsunami warning for parts of Mexico’s Pacific coast – there were 217 aftershocks by 4 p.m. Central Time Mnonday, the National Seismological Service (SNS) said. The largest of those was a 5.3 magnitude quake, which occurred just after 2:30 p.m. Monday with an epicenter 50 kilometers south of Tecomán, Colima.

However, the SNS reported a 5.8 magnitude quake with an epicenter 72 kilometers south of Tecomán, Colima, just after 3:15 a.m. Tuesday.