Santorin/Thira Volcano, Greece

Abstract

Santorin (Thira or also Thera in Greek) is a volcanic island (36°24′N, 25°24′E), actually a group of islands, in the Sea of Crete, belonging to the Cyclades Archipelago. The group consists of one large island (Thira) and five smaller islands (Thirassia, Aspronisi, Paleokameni, Neokameni, and Microkameni). Santorin, with the highest point of 566 m above sea level, presents the top of a large undersea volcano. The list of recorded volcanic activities confirms numerous large eruptions in prehistoric times, e.g., a gigantic explosion in 1650 BC and a number of smaller eruptions, e.g., in AD 1707–1710, 1866–1870 (the most famous eruptions), 1940– 1941, and 1950.

The Santorin group, located some 130 km north of Crete makes a complex of several overlapping shield volcanoes. Numerous basalt and andesite lava flows are nowadays exposed as rocky cliffs forming the inner caldera wall. There is an evidence of many large explosive eruptions that occurred there in the last 200,000 years. The island's present structure was formed by a huge eruption 21,000 year ago. Today, the islands, together with several rock cliffs scattered in the sea around, form a residual part of the submerged caldera of about 20 km in diameter belonging to a giant submarine volcano (Fig. 54).