Scientists identify 1831 volcano that turned the sun blue

Scientists from the University of St Andrews and the DRI identified the Zavaritski volcano as the source of a massive 1831 eruption that cooled the Northern Hemisphere.

The researchers solved a century old mystery by comparing volcanic ash trapped in Greenland ice cores with rock samples from the Kuril Islands. This eruption caused a severe cooling of approximately one degree Celsius, which triggered unusual weather and famines in regions including Europe, India, and Japan.

Historical records from the time, including notes by composer Felix Mendelssohn, described the sun appearing in shades of blue, purple, and green during the summer of 1831. The team led by William Hutchinson used chemical analysis on ice cores to pinpoint the eruption to the spring or summer of 1831. They discovered tiny pieces of volcanic glass in the ice, some ten times thinner than a human hair.

These microscopic fragments matched the chemical composition of the Zavaritski volcano located on the uninhabited Simuširu island. This island sits in the Kuril chain between Hokkaido, Japan, and Kamchatka, Russia. The eruption was so large it created a caldera three kilometers wide. Because the island is remote and often covered in fog, no written accounts of the event exist. Hutchinson noted that while the discovery helps map potential climate changing eruptions, predicting the next major event remains difficult.

The researchers suggest that identifying such volcanoes is essential for coordinating international responses to future climate changing volcanic activity.