If you happened to be at the right place in southern Mexico in the early 1980s, you might have encountered a strange-looking hill poking up from a thick tropical jungle. Covered in trees, it was known as ‘El Chichón’, the Spanish slang word for a small bump.
At the time, few realised the hill was a volcano, and those who did never expected it to do anything, since no activity had been observed in centuries. All that changed in the spring of 1982.
Back then, volcanoes were in the zeitgeist. Two years prior, the Mount Saint Helens volcano in the United States spectacularly blew half of its flank away. It would go down as one of the most iconic and studied eruptions in history, and an inflection point for modern volcanology.
The fact that the blast was sideways was unexpected and killed 57 people, but the eruption itself was anticipated through monitoring, and authorities evacuated more than 2,000 people in advance.
El Chichón, by contrast, caught everybody by surprise, with three separate explosive phases. It measured 5 on the volcanic explosivity index (VEI), which describes eruption scale – the same as Mt St Helens, as well as Vesuvius in 79 CE. Hot avalanches of rock, ash and gas flattened whole swaths of the jungle, setting off fires, damming rivers and destroying buildings.
Ash from the explosions covered regions 70 km away, collapsing roofs and creating mudflows (lahars), and volcanic particles even reached Guatemala. Little was known about the number of people living in this region at the time, but it is thought that at least 2,000 died and 20,000 were made homeless in Mexico’s worst volcanic disaster in modern times.
In 2006, I found myself looking down over El Chichón’s kilometre-wide crater. While I was retrieving samples from the hot, bubbling, acidic lake, which alternated from cyan blue to emerald green throughout the year, the ground shook as the geothermal gases fought their way to the surface – an unsettling reminder that I was in the crater of a very active volcano.
The trip was one of my most formative life experiences, and one story a local told me has stayed with me ever since. When the 1982 eruption began, their relatives had sought shelter in the village church from the heavy ash and pumice rain. They were found weeks later, along with dozens of other villagers – all dead under the collapsed roof, crushed under the weight of ash.