August M
Nearly half a century after one of the deadliest volcanic disasters in modern Mexican history, scientists are again watching El Chichón with unease.
New observations suggest subtle but persistent changes beneath the surface, raising questions about whether the long-silent volcano is beginning to stir, reports the Express.
A lethal history
El Chichón last erupted in 1982 in a series of violent explosions that devastated large parts of southern Mexico. High-sulphur blasts and anhydrite-rich magma destroyed the summit dome, sending lava flows and surges across an area roughly eight kilometres wide.
Within just over a week, three eruptions killed thousands, erased entire villages and forced mass evacuations, according to historical records cited by The Express. The disaster left a lasting scar on the region.
Ancient echoes
The volcano’s destructive potential may extend far beyond the 20th century. A 2017 research paper suggested that an eruption of El Chichón in the sixth century could have contributed to the collapse of the Mayan civilisation.
Scientists behind that study argued the eruption may have triggered a century-long “dark age” in the region, disrupting agriculture and society on a vast scale.
New warning signs
Now, volcanologists say El Chichón is no longer entirely quiet. According to environmental outlet Green Matters, researchers from the National Autonomous University of Mexico (UNAM) observed consistent movement inside the crater during the second half of 2025.
They recorded elevated temperatures, gas-driven bubbling and new sulphur formations. Inspections of the crater lake revealed hollow sulphur spheres, formed in the presence of liquid sulphur pools, alongside rising lakebed temperatures.
What’s driving it
Dr Mariana Patricia Jácome Paz, who studied the volcano between 2021 and 2025, said the changes suggest activity just beneath the Earth’s crust. Speaking in a recent lecture, she explained that the behaviour is likely driven by superheated groundwater reacting with hot rock.
“The observed behaviour is consistent with hydrothermal processes or minor steam-driven explosions,” Dr Paz said, adding that magma does not yet appear to be rising directly to the surface.
Watching closely
A 2025 paper by Dr Paz indicates early magma-hydrothermal interactions, a process that can build pressure and, in extreme cases, lead to explosive eruptions. Gas sampling has also shown increased hydrogen sulphide and carbon dioxide near the crater.
Mexican scientists stress that such emissions are common in active hydrothermal systems and do not necessarily signal an imminent eruption. For now, experts say there is no cause for public alarm, but continuous monitoring remains essential.
Sources: The Express, Green Matters, National Autonomous University of Mexico
