|2.0 The caldera wall at Fira on the island of Thera reaches
a height of about 220 meters. It represents a section of Santorini's volcanic history over
the span of nearly half a million years. At the very top are the white houses of Fira and
below the town the small harbor to which it is connected by a zigzag donkey path. The
distinctive hill of Skaros can be seen on the upper left.
Santorini and the Puzzle of Plate Tectonics
The volcanic islands that form a curved line across the Aegean were
produced by the convergence of two continental landmasses, Africa and Eurasia. This chain
has been named the South Aegean Volcanic Arc or Hellenic Arc. Santorini is today the only
active volcano in this arc; it has had three eruptions in this century alone.