The layers of volcanic deposits that have been left behind on the cliffs of Santorini's volcanic island are visible. Credit: Dr. Ralf Gertisser (Keele University)New research by Oxford Brookes University shows that the rise and fall in sea levels can influence the probability of volcanic eruptions on Santorini's Greek island. The researchers analyzed the eruption times over hundreds of thousands years to determine if eruptions are more likely to happen. These findings could have important implications for millions of people who live on volcanic islands all over the globe.The history of volcanic eruptions is revealed in SantorinicliffsDr. Christopher Satow, Senior Lecturer of Physical Geography at Oxford Brookes, led the research into the popular tourist destination.According to him, there are clues to past volcanic activity in Santorini's inner parts. He said that a massive eruption 3600 years ago caused the centre of what was then an island conical to sink into the ocean. This revealed an extraordinary detail of more than 200 volcanic eruptions."Comparing the eruption history with a sea-level record allowed us to demonstrate for the first time, that the sea level played an important role in determining when eruptions occurred at Santorini and possibly at other island volcanoes throughout the world."The mechanism is simple. Falling sea levels take mass from the Earth's crust, and the crust cracks. These fractures enable magma to rise, thereby allowing eruptions to occur at the surface.Researchers believe that fluctuations in sea levels may have also influenced eruptions on hundreds of volcanic islands all around the globe. Dr. Satow said, "Just like when you pull out a plug from a bath, the water level drops all around the bath at once; in the same way, sea levels change at the same moment everywhere on the planet."Animation of sea level affecting volcanic activity. Credit: Oxford Brookes UniversityClimate change and volcanic eruptionsVolcanic eruptions can alter the climate. The Philippines' eruption of Mt. Pinatubo's 1992 eruption caused a drop in global temperatures of 0.5 C.Dr. Satow claims that the climate has an impact on volcanic activity. "What's less known is the fact that the climate can also have a long-term effect on volcanoes. After the last ice age, as ice sheets receded across volcanic landscapes, the Earth's crust changed its stress conditions, which allowed for the formation of fractures that feed volcanic eruptions."As these melting ice sheets, the global sea level rose quickly, by about 100 meters, adding significant mass to the crust around volcanic islands, which in theory should alter their eruptionive activity."Dr. Satow concluded that 57% of the world's volcanic sites are either islands or coastal and often house large populations. To fully understand the impacts of rising sea levels on these volcanoes, and the risks they pose for their populations, more research is necessary.Dr. Satow worked with researchers from Keele University in Oxford, Royal Holloway University of London and Keele University.Nature Geoscience published "Eruptive Activity at Santorini Volcano Under Sea Level Rise and Fall".See more: Indonesia's Sinabung sends a column of volcanic ash into the skyMore information: Nature Geoscience, (2021) Eruptive activity of Santorini Volcano is controlled by sea-level rising and falling. www.nature.com/articles/s41561-021-00783-4 Journal information: Nature Geoscience Eruptive activity of the Santorini Volcano controlled by sea-level rise and fall,(2021). DOI: 10.1038/s41561-021-00783-4
