The Volcano

Santorini is one of the most studied volcanoes after the Vezuvious, because of its internal cleanness and built. During the whole of its history it is connected indissolubly with its volcanic activity, which formed its shape and its rare geological distinctiveness.

Various geological studies in the Helladic space have proven the existence of land where the Aegean Sea is today, which connected the Aegean with Crete and Asia. This land was called  Aegiida and consisted many mountains, followed by valleys and lakes. One of its mountain ranges Anatolikoegyptiaki, included Mount Profitis Ilias of Thira. In the following historic period Aegiida was dismembered into parts, some sinking and others not. Volcanic activity followed and at the midst of the 2nd Century , the largest  documented catastrophe, created a thick layer of pumice, and the ring complex of Santorini.

In prior ancient times Santorini was a small non-volcanic island, its remnants still visible from Profitis Ilias Mount, at the southeast side of the island, consisting of non volcanic limestone. As time passed, the underwater volcanoes formed magma on the west side of the island, creating a number of small islands. Gradually and about 500.000 years later, two giant volcano-shields were created and connected to the non volcanic island. Geologists have called the two mountains Peristeri and Thira.

About 200.00 years ago, the volcanic activity begun to increase. The mount Thira begun to produce large amounts of magma and ash until it eventually drained and the crater was empty. The shaky structure of the mountain collapsed inside the empty crater creating the Caldera. Caldera is word of Spanish origin, meaning stock pot.

The activity of volcanic prostration of Caldera in Santorini continued for the next 200.000 years in an entourage of eruptions, as the two mountains produced magma, collapsed, and recreated over and over again, until the Caldera finally started to look as it does today.

The Caldera now covers around 32 square kilometers of Santorini and the bed depth ranges from 300 to 600 metres. On the west side the Thirasia Island and the non-habitable Aspronisi are situated. The close observation of these three islands unravels the conceivable shape and size before the Caldera. The Caldera height ranges between 150 and 300 metres and her width between 2 and 6 kilometres.

The shape of the Caldera changed a number of times with the pass of time, because of volcanic activity but the last mass explosion is believed to have happened in 1645 BC.

This eruption was named Minoan explosion as it fell in the same time period as the Minoan civilization. The Minoans were people who were based in Crete, other islands and Santorini in the ancient times. Remains of their villages were found below the volcanic ashes in Santorini as well as Thirasia, disclosing a civilization with many buildings, sewage system, and murals. People however, were not found, and is believed the Minoans were warned off the island of Santorini, before the eruption.

The first part of the Minoan explosion was the blow of the Mount Thira top which created pumice, white stone with blebs, lighter than water. Where the island has not been cleared yet, you can find up to 5 metre pumice layers, which until recently with the Santorinian soil was a major part of the economy of the island. Up to two tons yearly were exported.

At the next phase of the eruption, large quantities of magma were exposed in explosive waves, looking like nuclear bomb mushrooms. Between the pumice and magma, 30-40 cubed kilometers of stone were blown away the volcano. At the last stage of the eruption, the magma chamber underwater emptied, the surface of the volcano collapsed deepening the Caldera and leaving vertical rocks visible today.

As the new Caldera deepened, water masses were shifted to the centre of the island while a number of islands begun to create, two of which are Palia Kameni and Nea Kameni. The last eruption was in 1950 in Nea Kameni and its remnants are still seen today.

Mount Peristeria seems to have disappeared today as there is no sign of the North part of the Caldera. Mount Thira did not blow away with the explosions but begun to gradually formulate till 197 BC when its peek emerged from the sea. It is said to continue to grow until another explosion takes place.

The Minoan explosion is considered as one of the biggest in the history of civilization and can only be compared to the volcano eruption of Mount Tambura in Indonesia in 1815.Relativelly; Santorini produced about 35 times more rock and ash from the eruption of Mount of St Helen in the U.S.A. in 1980. The eruption of Krakatoa in Indonesia in 1883, was slightly smaller than that of Santorini. To show the magnitude of the Santorini eruption, comparisons should be made with the Krakatoa eruption. It produced a tidal wave which killed 36000 people and was heard from 4500 kilometres away.

These days the volcano rests only producing steam and sulphurus gases. The gas temperatures can reach 86 Celsius degrees. Seven craters are found on the isle of Nea Kameni and one on the isle of Palia Kameni, whereas an underwater crater ‘Columbo’ lays on the Northwest of Santorini , close to Ia. The general volcanic activity is under daily observation by Greek seismologists of the Institute of Study and Observation Of the Santorini Volcano.

The massive catastrophe that took place years ago is the reason why the island has such a distinctive and rare beauty.

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