The mystery location of a giant volcanic eruption that occurred almost 200 years ago has finally been solved thanks to ash traces preserved in ice cores.
In 1831, famous composer Felix Mendelssohn wrote about the catastrophic weather during his summer journey through the Alps, remarking that “it is as cold as in winter, there is already deep snow on the nearest hills.”
Scientists suspected that this cold snap was caused by a massive volcanic eruption spewing sulfurous gas and ash into the atmosphere. This volcanic cloud layer reflected the sunlight, causing a global cooling of approximately 1 degree Celsius.
While scientists knew it was a major event, the identity of the volcano responsible remained unknown and fiercely debated, until now.
By analyzing traces of ash preserved in ice cores recovered from Greenland, the research team produced a chemical fingerprint of the lava, matching it to a volcano on a remote island on the other side of the world.
“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,” explains first author Dr. Will Hutchison from the School of Earth and Environmental Science at the University of St Andrews in the U.K.
Dr. Hutchison and his team were able to accurately date and match the ice core deposits to Zavaritskii volcano on the remote, uninhabited island of Simushir, part of the Kuril Islands. The islands are today a disputed territory between Russia and Japan.
“We analyzed the chemistry of the ice at a very high temporal resolution. This allowed us to pinpoint the precise timing of the eruption to spring-summer 1831, confirm that it was highly explosive, and then extract the tiny shards of ash. Finding the match took a long time and required extensive collaboration with colleagues from Japan and Russia, who sent us samples collected from these remote volcanoes decades ago.”
“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. 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.”
The volcano responsible for the 1831 eruption was very remote, yet it had a significant global impact on climate and severe consequences for human populations.
Identifying the sources of these mystery eruptions is crucial, as it allows scientists to map and monitor the regions on Earth most likely to produce climate-altering volcanic events.
“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,” concludes Hutchison.
The study, “The 1831 CE mystery eruption identified as Zavaritskii caldera, Simushir Island (Kurils),” was published in the Proceedings of the National Academy of Sciences and can be found online here.
Additional material and interviews provided by University of Andrews.
