Lake Atitlán. Image: © jesuschurion57 /Stock.adobe.com
Only a handful of super-eruptions have occurred in the past 100,000 years, scientists say.
Researchers from the University of St Andrews in Scotland have figured out when one of Earth’s largest known volcanic eruptions occurred by analysing microscopic ash particles in polar ice cores.
Researchers found ash particles in the extremely large volcanic sulphate deposit in Greenland and Antarctic ice cores, which hold detailed age and climate records. Through these records, scientists were able to date the Los Chocoyos super-eruption at the Atitlán volcanic system in Guatemala to 79,500 years ago.
Moreover, they determine that while causing devastating short-term disruption to global climate systems, the eruption did not have long-term effects on the climate, and in the decades that followed, temperatures eventually recovered to pre-eruptive conditions.
Super-eruptions are the largest volcanic eruptions known to have occurred on Earth. A super-eruption is an explosive volcanic eruption so massive that it causes a collapse of the volcano’s surface, creating a large crater-like depression called a caldera. They measure at eight or above on the Volcanic Explosivity Index (VEI) – a scale used to define the size of eruptions.
A VEI 8 eruption blows up 1,000km3 of rock, ash, lava and other material, as well as injecting large volumes of gasses into the upper atmosphere, including sulphur gasses. The gasses react to form sulphate aerosols, which reflect sunlight and act to cool the planet.
“Our findings improve our understanding of how resilient the climate can be to super-eruption-scale injections of stratospheric sulphate,” said Dr Helen Innes, lead researcher of the study, which was published in the Nature journal.
“Continuing to identify the largest volcanic eruptions in ice cores and assign high-precision ages is essential to our understanding of the risk that major stratospheric sulphate injections pose to global climate.”
The study is an important step in understanding super-eruptions, the risk they pose and the role they have in climate tipping points, the researchers said, especially as no super-eruption has occurred in recorded history, and only a few in the past 100,000 years. Moreover, according to the researchers, the most recent super-eruption occurred in Taupō, New Zealand, around 25,500 years ago.
Although recent findings suggest that super-eruptions occur more often than previously thought, they are still exceptionally rare, with some estimations suggesting that there is a 0.12pc possibility of one occurring in the next 100 years.
St Andrews’ researchers recently solved another volcanic mystery by identifying the location of an 800-year-old eruption which cooled the globe by approximately one degree Celsius. According to the scientists, the 1831 eruption occurred on a remote, uninhabited island currently disputed between Russia and Japan.
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