Santorini clue to volcano eruptions
John Swift: February 2012
Santorini clue to volcano eruptions.
Few visitors to the Greek Island of Santorini will be unaware of the island's volcanic birth in a cataclysmic eruption. Santorini's spectacular sunsets, a hot draw for thousands of holiday visitors, are a result of fumes from the smouldering volcano that lies in the heart of the flooded caldera.
More than 3,000 years after the super volcano blew Santorini sky high in a violent explosion, the island may hold clues into how scientist can forecast future eruptions.
An article in the journal Nature, claims that the molten-rock magma reservoirs in caldera volcanoes go through a 'pulsatory' period before they explode.
It was around 1630 BC that the super-volcano destroyed the original Aegean island of Santorini, an event so violent that some theorists believe that the tidal wave it caused destroyed the Minoan civilisation in nearby Crete. Others claim it triggered the legend of of the lost city of Atlantis.
The Santorini explosion was a caldera eruption, a volcanic event that only happens every few tens of thousands of years. Pressure in the volcano chamber builds up because there is no vent to release the molten rock.
Eventually it ends in catastrophe, with the top of the volcano ripped off in a cataclysmic explosion and leaving behind a huge bowl called a caldera, the Spanish word for cauldron. In Santorini's case the caldera has filled with seawater
Scientists want to be able to predict when such a massive explosion is due. Other calderas include the Yellowstone Park in the US which has already been classified as 'high-threat' in a US geological survey.
Now scientists working on Santorini has discovered a link between explosions and the mineral called feldspar. They found of magnesium, strontium and titanium, deposited by the slowly advancing magma. The chemicals give a tell-tale signatures of events over time.
From these signatures, the picture that emerges is of 'pulses' of magma injection in the years before a great eruption. Such pulses could today be detected by satellites and terrestrial motion sensors.
Long-term monitoring of caldera systems, even in remote parts of the world, is essential if late-stage growth spurts of shallow magma reservoirs are to be detected well in advance of caldera-forming eruptions, say the scientists
The Santorini island explosion was even bigger than the destruction of Indonesia's Krakatoa in 1883 and spewed out an estimated 14.4 cubic miles of ash that devastated Bronze Age civilisations in the Aegean.
Some say the event inspired Plato's tale, written some 1,300 years later, of the island empire of Atlantis that sank forever beneath the waves.