Santorini is considered one of the most attractive and violent volcano-calderas in the world. The first volcanic activity in the Cyclades likely took place some 2.5 million years ago, southwest of Santorini, and created a giant volcanic structure near the Christiani islets. In the island cluster around Santorini, magma first erupted about a million years ago. The location of the volcano around Santorini is controlled by a deep tectonic line, a large fault in the crust of the Earth which begins from the Christiani islets and terminates at the island of Amorgos. This fault remains active even today. When it shifted in 1956, it caused a massive earthquake that leveled the settlements on Santorini. «The volcano of Santorini, or Thera, is very important!» says Haraldur Sigurdsson, the Icelandic-born volcano expert who is now a professor at the Graduate School of Oceanography at the University of Rhode Island in the USA. «It is of special interest not only to Greece but to the entire world. The explosion during the Bronze Age is a landmark in the study of volcanos, an outstanding example of this kind of eruption. Even today it is believed to have been the second-largest explosion known to humanity after Tambora in Indonesia in 1815.» Sigurdsson has been studying the Santorini volcano since 1975. «Since then, I have been doing comparative and parallel research on the volcano of Krakatau in Indonesia,» he says. «The Krakatau eruption in 1883 killed 36,000 people. When it exploded, everything happened exactly as with the volcano in Santorini, the only difference being that Krakatau’s explosion created a giant [tsunami] 35 meters high which hit the coasts of Java, Sumatra and elsewhere. The question as to whether the Minoan-era explosion in Santorini created a tsunami is one of the questions we are exploring during this research trip.» Everything scientists know about Santorini’s volcano has been culled through observations of the island. However, the depths around the island have not been examined. When the pioneering current research is completed, many assumptions about the volcano and the effects of its explosions may be proven wrong. Consider, for instance, the theory that the eruption on Santorini was the second-largest in the world. If the size of the sea deposits of pumice and ash and the path of the lava are bigger than originally thought, this could indicate that the volcanic eruption on Santorini may have been the biggest ever.