Sex fira 16
The basement rock is primarily composed of metamorphosed limestone and schist, which date from the Alpine Orogeny.
These non-volcanic rocks are exposed at Mikro Profititis Ilias, Mesa Vouno, the Gavrillos ridge, Pyrgos, Monolithos, and the inner side of the caldera wall between Cape Plaka and Athinios.
The metamorphic grade is a blueschist facies, which results from tectonic deformation by the subduction of the African Plate beneath the Eurasian Plate.
Subduction occurred between the Oligocene and the Miocene, and the metamorphic grade represents the southernmost extent of the Cycladic blueschist belt.
The subduction compels the formation of the Hellenic arc, which includes Santorini and other volcanic centres, such as Methana, Milos, and Kos.
The inner coast around the caldera is a sheer precipice of more than 300 metres (980 ft) drop at its highest, and exhibits the various layers of solidified lava on top of each other, and the main towns perched on the crest.
The volcanic rocks present from the prior eruptions feature olivine, and have a small presence of hornblende.
It is the most active volcanic centre in the South Aegean Volcanic Arc, though what remains today is chiefly a water-filled caldera.
Thera is built upon a small, non-volcanic basement that represents the former non-volcanic island, which was approximately 9 by 6 km (5.6 by 3.7 mi).
It is the largest island of a small, circular archipelago, which bears the same name and is the remnant of a volcanic caldera.
It forms the southernmost member of the Cyclades group of islands, with an area of approximately 73 km (28 sq mi) and a 2011 census population of 15,550.
In recent years, Santorini has been voted one of the world's most beautiful islands (2015 Travelers” Choice Awards Reader's Choice Awards, amongst others).
Santorini remains the home of a small, but flourishing wine industry, based on the indigenous Assyrtiko grape variety.