History of the Volcano

 

The oldest volcano centres on the island are located in the area of Akrotiri. Geologic material at many locations on the island contains a large number of mineralized marine organisms. Radiocarbon dating indicates that the age of fossils ranges between 645,000 and 585,000 years. Some 50,000 years later the volcano of Peristeri was created between Therasia (Thirasia) and northern Thera. It is 400-metre high, its highest point today being the Mikros Profitis site. During the same period other volcanoes were activated, including Balos, Kokkini Paralia and Kokkinopetra. A period of big eruptions ensued with billions tonnes of tephra ejected into the air, part of which settled down on the island, thus shaping it. Ashes thrown up after the explosions were dispersed in the atmosphere of the whole planet. As a result of the series of furious eruptions, the volcano collapsed into itself, creating a huge basin, which was filled by sea. This basin is called caldera, which comes from a Spanish word meaning “cauldron”. Magma continued to gush out from the caldera at lower intensity, thus creating a new volcano. The volcano collapsed, was refilled and subsequently re-erupted 12 times in the past 400,000 years. Compact layers of lava visible in the precipice below the village of Imerovigli, as well as lava deposits on top of the cliffs of Therasia are what is left from the Skaros volcano. The beautiful village of Ia is built upon the red tephra, ejected in the volcano eruption 50,000 years ago.

 

 The Last Big Eruption

 

One of the volcano’s last big eruptions was in approximately 1650 BC. During that period the island was called Strongyle, which means “round”, due to its circular shape. The island formed an almost continuous ring between Pharos and Aspronisi. These two locations were separated by a channel, through which the sea flowed into a caldera, in the middle of which the top of an underwater volcano protruded. Months before the eruption, seismic activity was so intense that it caused substantial damage on the settlements, making the everyday life of the island’s inhabitants extremely difficult. It is likely that the volcano erupted in the spring, as the analysis of yellow mud from the central and southern part of Santorini, brought to light olive leaves and pollen grains from olive and coniferous trees. It has been estimated that 90 billion tonnes of melted rocks were ejected into the air within a few days. Volcanic tephra, having covered the whole island with a layer of ashes up to tens of metres thick, spread out in the atmosphere of the Earth. It is worth noting that even today ashes and sulphuric acid droplets have been retrieved from glaciers in Greenland. It has been scientifically established that the eruption caused a volcanic winter and a decrease in the temperature on the Earth by 1 - 2 °C.

The volcano collapsed creating the caldera of Santorini, as it is today, and generating a high tsunami which most probably destroyed the famous Minoan civilisation on the island of Crete, 110 km to the south of Santorini. As a result of subsequent milder volcanic activity the small islands of Palea Kameni and Nea Kameni were created in the centre of the caldera. Caldera cliffs still bear traces of ancient flora, providing significant information about the evolution of the flora in the area. In 197 BC, approximately 1,500 years after the caldera was created, a new island emerged on the sea surface.

The Volcano Today

 

Eight eruptions have been registered from the moment the undersea volcano was created, with its peaks the islands of Palea Kameni and Nea Kameni, until today. The last one occurred in 1950. Since then, the volcano has been inactive, but warm springs on the beaches of the island, as well as hot gases, still released from the craters of the island of Nea Kameni, are signs that it still exists. Studies conducted by volcanologists from all over the world suggest that a big and devastating eruption may occur in the future. The explosion could be comparable to the so-called “Minoan” one and could completely destroy Santorini, producing a serious impact on the entire Aegean region and the Eastern Mediterranean.