28-05-2025
Cataclysmic 1831 Eruption Traced to Quadruple Volcano on Abandoned Soviet Island
This Cold War outpost concealed more than submarines—it hosted a devastating eruption that cooled the planet nearly 200 years ago.
Scientists have finally solved a 200-year-old climatological mystery—and the answer was hiding out on a forgotten island. Late last year, a team of researchers revealed that a massive 1831 eruption from Zavaritski volcano, part of the remote Simushir Island chain, triggered global cooling in the Northern Hemisphere.
A newly released satellite image shows these peaks—Milna, Zavaritski, Prevo, and Uratman—lined up end-to-end in a near-perfect row, forming one of the most geologically dramatic landforms in the Kuril Islands, a disputed chain between Russia and Japan.
Simushir is part of the volatile Ring of Fire, where Earth's crust grinds and ruptures along tectonic plate boundaries. The 5-mile-long (8-kilometer) island features volcanic peaks visible from space. But one of them, it turns out, made an outsized and surprisingly recent impact on the world's climate. The team published its research describing the findings in the Proceedings of the National Academy of Sciences.
In 1831, the Northern Hemisphere cooled by nearly 2 degrees Fahrenheit (nearly 1.1 degrees Celsius), throwing the climate into disarray and painting skies strange hues. Scientists long suspected a massive volcanic eruption was to blame, but its source remained unknown—until now. The recent study revealed that Zavaritski, Simushir's relatively modest 2,047-foot (624-meter) volcano was the culprit. Ash from the eruption was later found in polar ice cores, solving the nearly 200-year-old mystery of which volcano triggered the global cooling.
'The moment in the lab when we analysed the two ashes together, one from the volcano and one from the ice core, was a genuine eureka moment. I couldn't believe the numbers were identical,' said volcanologist William Hutchison, a researcher at the University of St Andrews and lead author of the study, in a university release. 'After this, I spent a lot of time delving into the age and size of the eruption in Kuril records to truly convince myself that the match was real.'
Though the true identity of the volcano is a surprise, it's not shocking. Simushir's remote location and the fact its use by the Soviets as a secret nuclear submarine base kept it shrouded in secrecy for decades. (The Soviets used one of the island's flooded volcanic craters to dock its vessels). According to LiveScience, the island's military use ended in 1994, and the island is now abandoned—its calderas, bays, and rusting Soviet infrastructure slowly being reclaimed by nature.
Though none of Simushir's volcanoes have erupted since 1957, they still loom large—both literally and in historical memory. Milna, the tallest of the bunch at 5,050 feet (1,540 m), last erupted in 1914, and the volcano Zavaritski erupted in 1957. But others appear dormant; Uratman, the easternmost peak in the chain in the above image, may not have erupted for 12,000 years—hence it being a reliable harbor for Soviet subs.
The satellite image showcases a unique spit of land, one with a remarkable history of human occupation and world-altering volcanology.
