The frequent and strong earthquakes in Santoriniin Greece, reached magnitude 5.2 and caused the state of emergency statement, with thousands of people who abandoned the island. The origin of the shocks is linked to busty movements Along the edge between the African plaque and the Aegean microplacca. However, these events have aroused enormous concern in the population since Santorini is a volcanic island with one very long eruptive historystarted 2 million years agoduring which he continually changed appearance. Although – we remember – at the moment There is no evidence of an imminent eruptionthe history of the island is marked by one of the most catastrophic eruptions to which the man has witnessed, theMinoan eruptionwhich took place in 1613 BC The last eruption of Santorini dates back to 1950 and, since it is a Quiescent volcanosooner or later another will happen even if we don’t know when this will happen.
The early stages of the volcanic activity of Santorini
The volcanic activity in the Santorini area, in the Aegean Sea, is very ancient and characterized by eruptions both effusive and explosive: the first eruptions even date back to 2 million years ago And they took place on the bottom of the sea in correspondence with the current Akrotiri peninsula, in the southern part of Santorini. Over time, the materials emitted by the submarine volcano Akrotiri have accumulated until about 700,000 years ago They emerged from the waters originating an island. Recent studies have then identified testimonies of an explosive submarine eruption of enormous proportions, which occurred 520,000 years ago10 times more powerful than that of 2022 by Hunga Tonga-Hunga Haʻapai. Later, about 400,000 years agoin correspondence with the northern area of Santorini, it emerged Stratovulcano Peristeria. Starting from this period, the volcanic activity has moved to the center of the current Caldera: here, approximately 350,000 years agothe Thera shield volcanowho expanding the various volcanic islands in a single island.
The two main eruptive cycles of Santorini
Between 300,000 and 180,000 years ago The volcano Thera gave rise to a cycle of violent eruptions of explosive nature, which had the formation of a first caldera. A second erupting cycle took place Between 180,000 years ago and 1600 BC.: in this period of time at least they occurred Seven main eruptionsduring which the shield volcanoes grew in the caldera, such as that of Skaros (about 60,000 years ago) and that of Therasia (about 20,000 years ago). The violence of these eruptions destroyed vast portions of the great Thera shield volcano, determining their collapse several times. The shape of the island has changed around 25,000 years agoafter the explosion of the Capo Riva volcano: on this occasion about half of the island is sunk forming one New Caldera whose walls formed an almost continuous ring of islands, with a central volcanic cone.
The second eruptive cycle, which saw the alternation of violent explosions, with the formation of large heat, and the emergence of shield volcanoes inside them, has reached its climax in 1613 BC. In that year the volcano awakened, with a catastrophic eruption of Plinian type who issued approximately 60 km3 of pyroclastic materials: theMinoan eruption. The explosion, characterized by a volcanic explosiveness index (Vei) equal to 7 (The maximum value is 8) He made a quarter of the island sink, destroying the miniic settlement of Akrotiri. The fall into the sea of the materials emitted then caused one tsunami With waves more than 20 meters high, which has reached Crete, over 100 km away, devastating its coasts.
Santorini’s activity in the historical era
After the Minoan eruption, the volcanic activity led to the formation, in the central part of the Caldera, of Palea Kameni Islands (around the 197 BC) And Nea Kameni (towards the 1707 AD), while outside the Caldera the Kolumbo submarine volcano. Eruptions of particular relevance were those of Palea Kameni of 46 BC and of the 726 and those of Nea Kameni of 1570-73of 1707-11of 186-70of 1925-28of 1938-41 and finally of the 1950. The latter event lasted 22 days, but it was rather slight entity, accompanied by the formation of a small flat washing dome. The overall intake of large quantities of materials during the eruptive episodes in the historical era has meant that the dimensions of Nea Kameni increased considerably. Today Santorini is a volcanic complex in the shape of a crescent surrounding a large caldera, consisting of Thira islands, Thirasia And Aspronisy.
