Guatemala sits on top of three tectonic plates that really don’t get along. Known as Cocos, Caribbean, and North American, these chunks of Earth crust have tried to push, drag, and overtake each other for millions of years. Some may call this dynamic geology. I call it dysfunctional–especially when you tally up the myriad earthquakes and volcanic eruptions that have resulted from these petty land disputes.
Because of this battle underfoot, Guatemala is now home to more than 30 volcanoes–impressive when you consider the country’s only about the size of Tennessee. There’s Tajumulco, the tallest volcano in Central America at nearly 14,000 feet, and Santiaguito, the youngest lava-spewing mountain in the country, formed in 1922. Of course, there’s Volcan del Fuego, too, the volcano that erupted just yesterday outside of the colonial city of Antigua.
As lava and ash reportedly spewed into the sky and thousands were evacuated from villages in the Antigua area, I was a safe two-and-a-half-hours away in Panajachel, in my friend Ana’s kitchen, happily cooking away, oblivious to the world. It wasn’t until mid-afternoon when I started walking home that I realized something was amiss.
See, the clouds above me looked sick. The sky was a beautiful, brilliant blue, but the clouds themselves were a salmon-yellow-grey, the color of tomato-tinted dish water, a hue you get with a camera filter, not a hue you normally see in nature. Surely, I thought, this had to be a sign of something: an approaching hurricane, a tornado?
I called Shon to see if he knew what was going on, and he told me that Volcan del Fuego had burped, had belched a bit of ash and rock. A bit, but still enough to cover his office’s SUV–which was being used by a coworker near Antigua–with a coating of grey dust.
It wasn’t until I got home and online that I learned Fuego didn’t just have indigestion. There had been a real eruption with molten rock, hot gases, and smoke (it was all the ash in the air that made the clouds near us look ill). As I read about the unfolding disaster, a question that has irked me ever since arriving at Lake Atitlán once again flittered to mind: How do you really know that a volcano is inactive or extinct?
This is something that I occasionally ponder not just because there are three volcanoes (San Pedro, Atitlán, and Tolimán) that sit directly across from our house on Lake Atitlán, but because of the lake itself. See, Lake Atitlán is a 50-square-mile caldera that was formed some 84,000 years ago during an eruption called Los Chocoyos. A caldera is a cauldron-like depression in the earth’s surface that’s formed when a volcano erupts, and its emptied magma chambers cave in. In the case of Lake Atitlán, that depression filled with water over time.
Examples of other calderas include Crater Lake in Oregon and Yellowstone Caldera in Yellowstone National Park. You may recall that the latter is also as a steaming super volcano, thus implying that calderas can be active. Which leads me back to the original onerous question: How do you really know that a volcano is inactive or extinct?
It turns out, you can’t know. Not really. As the Smithsonian’s National Museum of Natural History puts it:
Because dormant intervals between major eruptions at a single volcano may last hundreds to thousands of years, dwarfing the relatively short historical record in many regions, it is misleading to restrict usage of “active volcano” to recorded human memories.
In other words, just because a volcano (or caldera) hasn’t erupted on our watch doesn’t mean it couldn’t erupt tomorrow. It may be extremely unlikely, but unlikely is not impossible.
In recent times, the three volcanoes across the lake from us have been relatively quiet. Atitlán’s last eruption was in 1853; the last time volcanoes San Pedro and Tolimán erupted is unknown. I don’t think the caldera has ever erupted, though it’s not without signs of life: Beneath the lake’s glassy waters is a fault line with warm volcanic mud.
Of course, I’m certain that if any of the formations around us were about to blow, there would be some warning, some indication. Volcan del Fuego regularly smokes and spits out ash; it threatens. Our volcanoes, meanwhile, remain quiet. They’re covered in thick, green forests, and plenty of people live at the base of each; they live all around the lake (caldera), too. I should find that comforting. But the thing is, no one can really predict when these sleeping giants might wake from their naps once more.