Mount Rainier looms over Seattle like a frozen guillotine, and roughly 3.7 million people live close enough to worry about it. Galeras in Colombia? It sits practically in the backyard of Pasto, a city of 450,000 souls who’ve gotten very comfortable living next to a geological timebomb that’s erupted more than 20 times since the 1500s.
Here’s the thing—most volcano monitoring in the late 1980s was reactive, not proactive. Scientists would scramble after eruptions, not before them. The Decade Volcanoes program changed that calculus entirely.
When the International Association of Volcanology Decided Sixteen Mountains Needed Babysitters
In 1991, the International Association of Volcanology and Chemistry of the Earth’s Interior launched what they called the Decade Volcanoes initiative. The name sounds bureaucratic because it was—this was the United Nations’ International Decade for Natural Disaster Reduction doing its thing. They picked sixteen volcanoes scattered across the globe, each one selected because it combined two delightful characteristics: a history of violent outbursts and way too many people living nearby.
The list read like a greatest hits album of geological anxiety. Vesuvius in Italy, obviously—it buried Pompeii in 79 AD and roughly 3 million people now live within its potential blast radius. Sakurajima in Japan, which has been erupting almost continuously since 1955 and sits just 8 kilometers from Kagoshima, a city of 600,000. Colima in Mexico. Mauna Loa in Hawaii, which makes up half the Big Island’s land mass and last erupted in 2022.
Wait—maybe the wildest part is that this wasn’t just about putting seismometers on dangerous peaks.
The program pushed for something more ambitious: genuine international collaboration, public education, hazard mapping that actually meant something. Scientists from wealthy institutions were supposed to partner with researchers in places like the Philippines (home to Taal volcano) or Indonesia (where Merapi kills people with depressing regularity—353 deaths in its 2010 eruption alone).
Turns Out Watching Volcanoes Saves Lives But Only If You Actually Do Something With the Data
Pinatubo wasn’t originally on the Decade Volcanoes list. Which is ironic, because its 1991 eruption became the poster child for why the program mattered. Scientists detected warning signs—increasing seismicity, sulfur dioxide emissions spiking—and convinced authorities to evacuate roughly 60,000 people. The eruption killed around 800 people, which sounds horrific until you realize tens of thousands would have died without those evacuations.
That success story made the Decade Volcanoes initiative look brilliant, even though Pinatubo wasn’t technically part of it. The program didn’t prevent eruptions—volcanoes don’t negociate. But it created networks, standardized monitoring techniques, trained local scientists who actually lived near these mountains.
Nevado del Ruiz in Colombia became a case study in what happens when you ignore warnings. It wasn’t on the original list either, but its 1985 eruption—which killed approximately 23,000 people in the town of Armero—haunted the program’s entire philosophy. Scientists had detected warning signs. Authorities dithered. Lahars (volcanic mudflows, basically cement trucks made of rock and ice) buried the town.
The Program Ended in 2000 But the Volcanoes Didnt Get the Memo
The formal Decade Volcanoes program wrapped up when the calendar hit 2000. Some of the sixteen mountains stayed quiet. Others didn’t.
Unzen in Japan, which killed 43 people including volcanologists Harry Glicken and Katia and Maurice Krafft in 1991, eventually calmed down. Nyiragongo in the Democratic Republic of Congo erupted in 2002, sending lava flows through Goma and displacing 400,000 people. Rainier has stayed quiet, but seismic monitoring has only intensified—the USGS now runs a network of sensors because “maybe it won’t erupt” isn’t a solid emergency management strategy for the Seattle metro area.
The program’s real legacy wasn’t the specific sixteen volcanoes. It was proving that monitoring works, that international cooperation beats nationalist science hoarding, that you can convince governments to spend money on disaster prevention if you frame it correctly.
Santorini in Greece, another Decade Volcano, erupted around 1600 BC and possibly triggered the collapse of the Minoan civilization. These days it’s a tourist destination where people sip wine and watch sunsets, blissfully unaware they’re standing inside a caldera that could absolutely wake up again. The monitoring equipment scattered across the island exists because the Decade Volcanoes program established that watching geological timebombs isn’t paranoia—it’s basic public safety.
Some volcanoes give you weeks of warning. Others give you hours. A few give you nothing at all, just sudden violence and ash clouds that ground aircraft across continents. The Decade Volcanoes program bet that knowledge beats ignorance, that sensors and seismographs and gas measurements could stack the odds in humanity’s favor.
Turns out that bet mostly paid off, even if the house always keeps a few cards up its sleeve.
