Sea levels influence eruptions on Santorini
The rise and fall of sea levels influence the likelihood of volcanic eruptions on the Greek island of Santorini, new research published in Nature has discovered.
Analysing the timings of eruptions over hundreds of thousands of years, the researchers found that a 40 metre fall in sea level is a crucial point beyond which eruptions are more likely to occur.
The findings could have implications for millions of people living on volcanic islands around the world.
Dr Andrew Miles, Lecturer in Igneous Petrology at the University of Leicester said: “What’s interesting about these results is that while volcanoes are known to have an impact on the Earth’s climate through the emission of ash and volcanic gasses, these data indicate that the reverse is also true for some island volcanoes.
“During colder periods of Earth history, large volumes of water are locked up in ice sheets and global sea levels fall. Lower sea level reduces the downward pressure on the underlying magma chamber and makes it easier for fractures and magmas to propagate from depth towards the surface.”
Clues about past volcanic activity on Santorini are embedded in the layers of rock on the cliff face encircling the inner part of the island. The researchers say that eruptions at hundreds of other volcanic islands around the world may also have been influenced by fluctuations in sea level
Dr Chris Satow from Oxford Brookes University said: “A huge eruption 3,600 years ago caused the centre of what was then a conical island to sink into the sea, revealing an extraordinarily detailed history of over 200 volcanic eruptions preserved within the remaining circle of cliffs.
“Comparing this eruption history to a sea level record allowed us to show for the first time that the sea level has had an important role in determining the timing of eruptions at Santorini, and probably at many other island volcanoes around the world.
“The mechanism is quite simple: falling sea levels remove mass from the Earth’s crust and the crust fractures as a result. These fractures allow magma to rise and feed eruptions at the surface.”
‘Eruptive Activity of Santorini Volcano Controlled by Sea Level Rise and Fall’ is published in Nature Geoscience. The research received funding from RCUK | Natural Environment Research Council (NERC) and Vetenskapsrådet (Swedish Research Council).