Sea level rise reduces volcanic eruptions
Santorini erupts when water levels are low.
Sea levels have affected volcanic eruptions on the Greek island of Santorini over the past 360,000 years. Research in Nature
Geoscience found that lower sea levels, which happen during ice ages, were linked to higher rates of eruption. The researchers believe this result likely holds true for other island volcanoes.
“The mechanism is quite simple,” says Christopher Satow, senior lecturer in physical geography at Oxford Brookes University, UK, and lead author on the paper.
“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.”
This mechanism has been proposed by researchers before, but the Santorini caldera volcano allowed Satow and colleagues to firm up the theory.
“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,” says Satow.
“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 researchers determined that 208 of the 211 eruptions that had occurred on Santorini over the past 360,000 years had happened when sea levels were at least 40 metres below their current levels.
While we know that volcanic activity can have short-term effects on the Earth’s climate, “what is less well-known is that on long timescales, the climate can also affect volcanoes,”
Satow says.