It is not only the fascination of its craggy precipices, the legend of the
lost island of Atlantis, the contrast between the deep blue of the sea, the
white of the pumice stone or the black intensity of the lava that make Santorini
unique.
Nor is it just the lovely little bars from which classical music floats
out discreetly to greet the lights around the caldera as the evening draws
in to a close.
Santorini has one of the most violent volcanoes on the face of the earth;
a huge, open-air, geological and volcanological museum, unique in the world.
The geological situation in the Aegean region is determined by the sinking
of the African lithospheric plate under the Eurasian plate. The African
plate is sinking to the South of Crete, under the Aegean, as it is moving
to the Northwest, at a speed estimated at 4 to 5 cm each year. This process
has been going on in the last 15 million years at a depth ranging from 120
to 140 km. At such depth, the presence of the submerged lithospere in the
earth's crust creates appropriate conditions for magma generation.
The last huge eruption of the volcano dates back 3,600 years, in the late
bronze age. This was a period when the island was vibrant with life and
movement, enjoying a flourishing civilisation similar to that of Minoan
Crete. This tremendous eruption, known as the "Minoan eruption",
ejected into the air 30 cubic kilometers of magma in the form of pumice
and volcanic ash,to a height of up to 36 kilometers above the island, even
seen in Norway. Pumice deposits, dozens of meters thick, buried one of the
most prosperous pre-historic settlements of that period, feeding the myth
of lost Atlantis
The removal of such a large volume of magma caused the volcano to collapse,
producing the Caldera. This catastrophe, gave rise to the legend of the
Lost Atlantis. Where the island of Strongyli, (which means "round island",
as we called the island before this eruption), once flourished in the brilliance
of its civilisation; there now gaped a yawning crucible which the sea rushed
to fill. Thira, Thirassia and Aspronissi: these are all that remain of Strongyli.
The eruption probably caused the end of the Minoan civilization on the island
of Crete, because of the immense seawaves.
Two million years have passed since the molten rock, the magma, first broke
out of the depths in which it was formed, to appear on the surface of the
earth here in this spot. It has taken thousands of eruptions since then
to build up again the volcano of Santorini. In the last 400,000 years there
have been more than 100 eruptions, each of which added a new layer of earth
and rock, slowly making the volcano bigger
Since 1969, intense archeological excavations have brought to light an
important Cycladic town , Akrotiri, which had been buried beneath the Minoan
ash-layer for almost 4000 years. Although it appears that people had time
to evacuate their island in time before the eruption, carrying most of their
goods with them, the findings from Akrotiri are impressive: especially,
they include well-preserved and magnificent wall paintings, ceramics and
other objects.
The eruption of 1926
The mild activity of the volcano after this major eruption continues into
the present (the most recent eruption occurred in 1950) building up two
small vulcano islands in the center of the caldera, Palea and Nea Kameni.
They are the youngest volcanic lands now in the Eastern Mediterranean. Palea
Kameni (Old Burnt Island) is less than 2000 years old, while Nea Kameni
(Young Burnt Island) began to form only 425 years ago and its youngest lavalayers
are less than 55 years old. These islands represent the volcano's most recent
activity. Eleven eruptions since 197 B.C. have formed the two islands. The
most recent eruption at Santorini was in 1950 on Nea Kameni, the northern
island. The eruption was phreatic and lasted less than a month. It constructed
a dome and produced lava flows. Interesting link : the "Institute for the Study and Monitoring of the Santorini Volcano