Eruption Risk for Santorini’s Volcano Determined by Past Sea Levels

A huge volcanic eruption on the Greek island of Santorini is thought to have caused the collapse of one of the greatest civilizations of the era three and a half thousand years ago. New research has shown that the possibility of this volcano flying back to its top could be shaped by sea-level rise.

This discovery could improve our ability to predict volcanoes on other volcanic islands – which is extremely important for those living nearby. Today, Santorini is a small island that is popular with tourists – but 3,700 years ago it was part of a much larger island, than the center of Minoan culture. Unfortunately for the Minoans, their island sat on a huge volcano and erupted about 3,600 years ago. It placed a string of small islands on the Caldera rim and launched a tsunami that uprooted the heart of Minoan culture in Crete.

Volcanoes have erupted many times before, though generally less explosively. In Nature Geoscience, researchers have reported that the cycles they have observed are driven by the eastern seabed. In addition to making history, the Minoan volcano uncovers cliffs on the remaining islands that preserve records of 211 past volcanoes in the last 360,000 years.

Lead researcher Dr. Christopher Satow of Oxford Brookes University said in a statement, “By comparing the history of these eruptions with sea-level records, we were able to show for the first time that sea surface Santorini and possibly other islands of the world played an important role in determining the timing of volcanic eruptions.” “The process is quite simple: falling sea level removes mass from the earth’s crust and consequently breaks the crust. These fractures allow magma to grow and allow surface eruptions to feed.

However, there is a long delay between fractures and eruptions. All but three of the 211 eruptions occurred 11,000 years later when sea levels were at least 40 meters (131 feet) below current levels. Santorini is now heading for a safer time due to rising oceans towards the end of the last ice age, so the threat of a 2012 eruption may not recur often. The effects of volcanoes on climate are well-known, with ash blocking the sun and causing short-term cooling, sometimes after long-term warming driven by carbon dioxide release, Sato says:

“What is less well known is that climate can also affect volcanoes in the long run.”