The University has become a spokesperson for seismic activity in the country
At the forefront of seismic monitoring; the 85 earthquake and its imprint on UNAM
The seismic event of September 19, 1985, made it clear the need for a surveillance system capable of operating 365 days a year, 24 hours a day, with state-of-the-art technology and an extensive network of well-distributed seismic stations throughout the country, as explained by Professor Carlos Valdés González from the Institute of Geophysics (IGf) at UNAM.
According to the researcher, the earthquake not only left its mark on the collective imagination of those who experienced it and those who have grown up in Mexico City since then, accustomed each year to revisiting the images left by the journalistic records, but it also led to the construction of a new culture of civil protection, prevention, risk management, and surveillance.
Valdés González, a committed promoter of Mexico’s National Risk Atlas platform, explained that the study of seismic activity in Mexico also suffered the consequences of the 85 earthquake; a date that will mark 40 years since its occurrence, signifying a turning point for the entire geophysical sector in our country, as it revealed a series of previously unknown aspects of the Mexican subsoil.
“The 85 earthquake had its epicenter off the coast of Michoacán, in an area where seismic movements of that magnitude (8.1) had not been recorded, at least in the last two centuries, so we believed it was a site where earthquakes did not occur. Confirming that it was not the case helped us better understand the complexity of the national territory, as Mexico’s seismicity is found in very different places.” This event allowed for a deeper understanding of Mexico City’s behavior towards such events, presenting a valuable opportunity to develop improved Civil Protection protocols and emergency response mechanisms following such phenomena.
“Part of the capital was built on what was once a lake, with some neighborhoods constructed on clays (sediments saturated with water that behave like gelatin), while others are settled in what was the lakeshore (or transition zone). These characteristics generate an amplification of seismic waves (particularly where the lake was located), known as the ‘Mexico City effect’.”
Through studies conducted at UNAM regarding the composition and behavior of the city’s soils, the University has been able to produce seismic mappings every year, presumed to be more detailed with each release. This work has enabled researchers from the Faculty and the Institute of Engineering at the National University to collaborate on developing specific construction codes for each area, as “Building a structure in what used to be the lake zone is not the same as, for example, at CU, located on what we call hard ground.”
According to the geophysicist, following the 85 earthquake, experts realized that seismic monitoring in Mexico had to be carried out full-time, leading to a myriad of technological and infrastructural improvements within the National Seismological Service (SSN), an organization led by the risk manager in two periods, from 1993 to 1996, and then from 2005 to 2014. “The events of 1985 made it clear that more resources and budget needed to be allocated, transitioning from analog to digital, installing more stations, and maintaining continuous observation.” Today, the SSN monitors seismic movements 365 days a year, 24 hours a day.
“What were you doing?” is a common question in conversations about earthquakes. In the case of Víctor Espíndola Castro, another professional in the field, he was a student on that day in September 1985, attending classes at the Faculty of Sciences while working as a reader at the SSN; “On the morning of that Thursday, September 19, I was heading to Ciudad Universitaria when I felt the earth’s movement. I rushed to the Seismological Center as quickly as I could to assist in the calculations and determine the earthquake’s origin.” That day, Víctor had to get to work and perform his duties based on the information provided by the few seismological stations available at that time, and on very large maps, with compasses and rulers. “It was all geometry.”
Today, Espíndola is in charge of the Analysis area at the SSN and states in his testimony that things have changed. The calculations that were previously done by hand, with pencil and paper, are now processed digitally, using cutting-edge equipment and algorithms that allow for nearly instant data retrieval, a process that used to take hours. The Ph.D. in Sciences affirms that the 85 earthquake highlighted that the twenty seismic stations that had been operational for four decades were insufficient to monitor the entire national territory, leading to the creation of a much broader network, currently consisting of over 100 monitoring stations installed and managed by UNAM. This extensive network enables the Seismological Center to obtain almost real-time data, accessible to users on social media through the SSN’s account or directly on the website, where what was once said as ‘it seems like there was an earthquake’ can now be confirmed through posted information, including magnitude and epicenter details.
From all this, it is evident that UNAM has become the spokesperson for seismic activity in Mexico. Nowadays, the University’s Seismological Center knows that the movements of the Earth’s crust are constant and works daily to acquire and train in the use of increasingly sophisticated equipment:
“When I took over as head of the SSN in 1993,” recalls Carlos Valdés, “we recorded about 300 earthquakes a year in the country. Now, the records for 2024 alone amounted to 33 thousand. This does not mean that earthquakes occur more frequently now, but rather that we have more stations and better equipment, allowing us to perform our work much better and detect even small events, such as micro-earthquakes in Mexico City.”
It is impossible to determine when the earth will shake; earthquakes are not predictable. So, strictly speaking, the earthquake season runs from January 1 to December 31. However, Mexicans have a reliable institution to monitor seismic activity across the national territory, all the time, managed by a university, not the government, a characteristic that, according to Valdés González, shields it from political conflicts, as its only commitment is to science and the population.
Key Takeaways:
– The 1985 earthquake in Mexico led to significant advancements in seismic monitoring and research, shaping a new culture of civil protection and risk management.
– UNAM has established itself as a leading institution in seismic monitoring, utilizing a vast network of monitoring stations to provide real-time data to the public.
– Continuous improvements in technology and infrastructure have enhanced Mexico’s ability to monitor and respond to seismic events effectively.
– The seismic activity in Mexico remains a constant focus of study and innovation, ensuring the safety and preparedness of the population against future earthquakes.
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