Another Sept. 19 Earthquake in Mexico? Scientists See a Coincidence

As Mexico prepares for its Second National Earthquake Drill on September 19, 2025, a familiar question resurfaces: Will there be an earthquake on this historically significant date? According to researchers at the National Autonomous University of Mexico (UNAM) and the National Seismological Service (SSN), the answer is rooted in science, not superstition.

( Sept. 19 update: The earthquake drill went fine )

Researchers emphasize that the coincidence that major earthquakes struck Mexico on September 19 in 1985, 2017, and 2022 is purely statistical and has no scientific significance. Luis Quintanar Robles, a researcher in UNAM’s Geophysics Institute Seismology Department, explained that earthquakes occur throughout the year and are frequent, making it impossible to predict when they will happen on specific dates.

The September 19 date has become deeply embedded in Mexico’s collective memory. The magnitude-8.0 earthquake on September 19, 1985, was the deadliest in Mexican history, with official casualties around 10,000, though some organizations estimate up to 40,000 deaths. Exactly 32 years later, on September 19, 2017, a magnitude-7.1 earthquake struck, killing around 370 people and causing extensive damage in Mexico City. Then, in 2022, a magnitude-7.7 earthquake shook the Michoacán coast on the same date, occurring less than an hour after the annual earthquake drill.

This string of coincidences has led many Mexicans to view September as “earthquake month.” However, scientific analysis of Mexico’s earthquake record from 1787 to 2022 reveals that April and December actually have more date coincidences (11 and 10, respectively) than September (4). The data clearly shows that September is not a special time when large earthquakes are likely to occur.

The Science Behind Earthquake Timing

The scientific consensus on earthquake prediction is clear. Neither the USGS nor any other scientists have ever predicted a major earthquake, and they do not expect to know how in the foreseeable future. An earthquake prediction must define three elements: the date and time, the location, and the magnitude — something current science cannot accomplish.

Even when examining the relationship between Mexico’s 2017 earthquakes, researchers found that while an 8.1 magnitude earthquake and a 7.1 magnitude earthquake occurring just 12 days and 600 kilometers apart had only a 1 in 30,000 chance, this remains a coincidence rather than a predictable pattern.

According to SSN data, July 2025 has been the most seismically active month in Mexico this year, with 3,501 earthquakes reported — a reminder that seismic activity continues year-round without regard to calendar dates.

National Drill Preparations

Mexico’s Second National Earthquake Drill will take place on September 19, 2025, at 12 p.m. Central Time nationwide, simulating an 8.1-magnitude earthquake and alerting 80 million phones. The drill will involve 14,490 loudspeakers across Mexico City and 10 states: Guerrero, Oaxaca, Chiapas, Michoacán, Jalisco, Colima, Morelos, México state, Puebla, and Tlaxcala.

President Claudia Sheinbaum has called the drill “one of the most relevant prevention and civil protection exercises” that Mexico will stage this year. Civil Protection coordinator Laura Velázquez Alzúa noted that the drill “not only promotes a culture of prevention but also allows us to evaluate emergency protocols and inter-institutional coordination.”

The timing of the drill, while commemorative, has created eerie coincidences. The 2017 earthquake occurred just two hours after that year’s drill, while the 2022 earthquake struck less than an hour after the exercise. Environmental seismologist Celeste Labedz described the 2022 occurrence as an “astounding coincidence.”

Earthquake Preparedness Over Prediction

While Mexico cannot predict when earthquakes will strike, the country has significantly improved its response capabilities. The SSN now operates 63 real-time stations and collaborates with regional networks to receive data from more than 160 stations, with plans to install over 50 additional stations. Current technology allows earthquake information to be published within minutes, compared to the several hours it took during the 1985 earthquake.

Authorities recommend using drills to identify safe places, escape routes, and prepare emergency “go bags” with nonperishable food, water, first aid supplies, flashlights, and important documents. For residents of Yucatán, while the peninsula has no fault lines and rarely experiences earthquakes, distant events can still be felt, as demonstrated when a 2017 Chiapas earthquake was felt in Mérida.

The message from Mexico’s top seismologists remains consistent: earthquakes can occur at any time, regardless of the date. As UNAM researchers note, earthquakes happen randomly in time and space, meaning Mexico must maintain constant preparedness rather than focusing on specific dates.

September 19 may live in Mexico’s earthquake memory, but science shows that preparedness, not calendar watching, offers the best protection against seismic threats. The U.S. Geological Survey reinforces this scientific consensus, stating that earthquake prediction remains impossible despite decades of research efforts worldwide.