Zavaritsky volcano identified as source of 1831 climate changing eruption and blue sun reports
Researchers pinpointed the Zavaritsky volcano as the source of the massive 1831 eruption that caused global cooling and turned the sun blue. The discovery connects sulfur deposits in polar ice cores to a previously overlooked volcanic event in the remote Pacific.
Satellite imagery of Simushir Island captured on November 30, 2024, showcases the Zavaritsky caldera, the confirmed site of the massive 1831 volcanic eruption. Image credit: CopernicusEU/Sentinel-2, EO Browser, The Watchers
- Researchers have identified the Zavaritsky volcano on Simushir Island, Kuril Islands, as the source of the massive 1831 eruption that cooled the Northern Hemisphere’s climate by 1 °C (1.8 °F) and caused global weather anomalies.
- The eruption injected approximately 13 teragrams (Tg) of sulfur dioxide into the stratosphere and triggered atmospheric phenomena like blue and green suns which contributed to severe famines in India and Japan.
- Advanced analysis of polar ice cores and ash samples provided a definitive chemical match and solved a 200-year-old mystery of the 1831 volcanic event.
Researchers from the University of St Andrews confirmed that the massive 1831 eruption was caused by the Zavaritsky volcano on Simushir Island in the Kuril Islands.
“The moment in the lab when we analyzed 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,” Dr. William Hutchison, the lead researcher, described.
The study involved analyzing microscopic ash shards extracted from polar ice cores and comparing their chemical composition with samples collected from the Zavaritsky volcano.
The results revealed a perfect match by linking the ash to the massive volcanic event that cooled the planet.
The eruption occurred at Zavaritsky volcano on Simushir Island, part of the Kuril Islands, a disputed territory between Russia and Japan.
The event injected approximately 13 Tg of sulfur dioxide (SO2) into the stratosphere leading to a 1 °C (1.8 °F) temperature drop in the Northern Hemisphere between 1831 and 1833.
The cooling effect resulted in widespread crop failures and contributed to famines in India (1832–1833) and Japan (1832–1838).
Reports of blue, purple, and green sun appearances in 1831 were attributed to light scattering caused by volcanic aerosols.
“Desolate weather, it has rained again all night and all morning, it is as cold as in winter, there is already deep snow on the nearest hills,” Felix Mendelssohn, the German composer, documented the unusual summer weather and stated.
Ash analysis and the “fingerprint match”
The research was made possible through advancements in analyzing volcanic ash.
“Only in recent years have we developed the ability to extract microscopic ash shards from polar ice cores and conduct detailed chemical analyses on them. These shards are incredibly minute, roughly one-tenth the diameter of a human hair,” Dr. Hutchison explained.
Ash samples from the Zavaritsky were collected decades ago by Japanese and Russian researchers and were compared with shards found in ice cores from Greenland. The geochemical profiles of these ash shards matched perfectly, providing definitive evidence of the eruption’s source.
Eruptive scale and characteristics
The eruption was classified as a magnitude 5 to 6 event based on the estimated erupted volume of 3.3 to 4.5 km3 (0.8 to 1.1 mi3). The sulfur emission was comparable to the 1991 eruption of Mount Pinatubo which also caused a global cooling of 1 °C (1.8 °F).
The caldera formed by the eruption is approximately 3 km (1.9 miles) wide and reveals layers of past volcanic deposits in red, black, and white. The caldera became a focal point for research into the eruption’s scale and impact.
Implications for modern science and preparedness
“There are so many volcanoes like this, which highlights how difficult it will be to predict when or where the next large-magnitude eruption might occur,” despite solving the mystery, Dr. Hutchison focused on the challenge of predicting future volcanic events.
The Kuril Islands remain one of the most volcanically active yet poorly studied regions on Earth. No modern monitoring equipment is currently installed on Zavaritsky or its neighboring volcanoes leaving the region vulnerable to undetected eruptions.
A puzzling climatic event
The 1831 eruption’s effects were first noted in polar ice cores where sulfur and ash deposits indicated a large stratospheric injection.
The event was mistakenly attributed to other volcanoes at the time including Babuyan Claro in the Philippines and Ferdinandea in the Mediterranean. The theories were later disproved because of discrepancies in sulfur output and ash composition.
The Kuril Islands’ remote location and sparse historical records allowed the Zavaritsky eruption to remain undetected for nearly two centuries.
The uninhabited Simushir Island, often enveloped in fog, had minimal human presence which reduced the chances of direct observations.
Technical advancements and future research
The study used advanced techniques to examine sulfur isotopes and crypto tephra which is microscopic volcanic ash found in ice cores. The approaches offered accurate dating and chemical signatures for the ash which allowed researchers to trace its origin.
Future research aims to map the distribution of Zav-1 tephra (volcanic deposits from the eruption) and conduct melt inclusion analysis to estimate the pre-eruptive magma composition.
“As scientists and as a society, we need to consider how to coordinate an international response when the next large eruption, like the one in 1831, happens,” Dr. Hutchison concluded.
Geological summary
Zavaritsky volcano stands at an elevation of 1 567 m (5 141 feet). The volcano consists of a series of 6 northwest-southeast trending cinder cones and an explosion crater. The features are near the headwaters of the Levaya Avacha River, west of the Eastern Volcanic Zone of Kamchatka.
The highest cone, Mount Peschanaya, rises to 1 567 meters (5 141 feet) near the southern end of this volcanic complex.
Eruptive activity at Zavaritsky has been recorded during 2 confirmed Holocene events. The volcano experienced an eruption around 850 BCE with a Volcanic Explosivity Index (VEI) of 4. Another eruption occurred in approximately 800 BCE and was classified with a VEI of 2.
The eruptions produced lava flows that blocked the Levaya Avacha and Ozernaya rivers and created Lake Vulkanischeskoe. Other related cinder cones are found northwest and northeast of Zavaritsky and contributed to its complex geological history.
The volcano’s location within a subduction zone and over continental crust exceeds 25 km (15.5 miles) in thickness.
References:
1 St Andrews researchers solve 200 year volcanic mystery – University of St Andrews – December 30, 2024
2 The 1831 CE mystery eruption identified as Zavaritskii caldera, Simushir Island (Kurils), William Hutchison, Patrick Sugden, Andrea Burke, and Gill Plunkett, PNAS, December 5, 2024 – https://doi.org/10.1073/pnas.2416699122
3 Zavaritsky – GVP – Accessed on January 11, 2025
Rishika holds a Master’s in International Studies from Stella Maris College, Chennai, India, where she earned a gold medal, and an MCA from the University of Mysore, Karnataka, India. Previously, she served as a Research Assistant at the National Institute of Advanced Studies, Indian Institute of Science, Bengaluru, India. During her tenure, she contributed as a Junior Writer for Europe Monitor on the Global Politics website and as an Assistant Editor for The World This Week. Her work has also been published in The Hindu newspaper, showing her expertise in global affairs. Rishika is also a recipient of the Women Empowerment Award at the district level in Haryana, India, in 2022.
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