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Santorini caldera is a large, mostly submerged caldera, located in the southern Aegean Sea, 120 kilometers north of Crete in Greece. Visible above water is the circular Santorini island group, consisting of Santorini (classic Greek Thera), the main island, Therasia and Aspronisi at the periphery, and the Kameni islands at the center. It has been designated a Decade Volcano.

Santorini Caldera
Santorini island group from space
Highest point
Elevation	367 m (1,204 ft)
Coordinates	36°23′44″N 25°27′33″E
Geography
Location	Aegean Sea, Greece
Geology
Mountain type	Caldera (active)
Last eruption	January to February 1950

Geography

The caldera measures about 12 by 7 km (7.5 by 4.3 mi), with 300 m (980 ft) high steep cliffs on three sides.

There are two small volcanic islands at the center of the caldera, Nea ("New") Kameni and Palea ("Old") Kameni.

The main island, Santorini has an area of 75.8 km² (29.3 sq mi), Therasia 9.3 km² (3.6 sq mi), and the uninhabited islands of Nea Kameni 3.4 km² (1.3 sq mi), Palea Kameni 0.5 km² (0.19 sq mi) and Aspronisi 0.1 km² (0.039 sq mi).

Santorini's high walls, draped by whitewashed villages, combined with a sunny climate and good observation conditions, have made it a magnet for volcanologists,[1] as well as a highlight of tourism in the Aegean.

Geology

The volcanic complex of Santorini is the most active part of the South Aegean Volcanic Arc, which includes the active volcanoes of Methana on the mainland of Greece, Milos, Santorini and Nisyros. It is formed by the subduction of the African tectonic plate underneath the Aegean subplate of the Eurasian tectonic plate, which occurs at a rate of up to 5 cm per year in a northeasterly direction. This subduction causes earthquakes at depths of 150–170 km.[2]

Non-volcanic rocks are exposed on Santorini at Mikro Profititis Ilias, Mesa Vouno, the Gavrillos ridge, Pirgos, Monolithos and the inner side of the caldera wall between Cape Plaka and Athinios.[3]

The Kameni islands at the center of the caldera are made of lava rocks.

Volcanology

The caldera of Santorini lies in the center of the Christiana-Santorini-Kolumbo volcanic field, which comprises the extinct Christiana Volcano, the Santorini Caldera, the polygenetic submarine Kolumbo Volcano, as well as the Kolumbo Volcanic Chain. [4] This volcanic lineament evolved during four main phases of volcanic activity, which initiated in the Pliocene from several local centers that only recently matured to form the vast Santorini edifice. The present-day caldera is composed of overlapping shield volcanoes, cut by at least four partially overlapping calderas, of which the oldest southern caldera was formed about 180,000 years before the present era (BP). The subsequent Skaros caldera was created about 70,000 years BP, and the Cape Riva caldera about 21,000 years BP. The current caldera was formed about 3600 years BP during the Minoan eruption.[5]

Palea Kameni and Nea Kameni were formed as a result of multiple, initially submarine, smaller eruptions at the center of the caldera.[6]

Although dormant, Santorini is an active volcano. Numerous minor and medium-sized, mainly effusive, eruptions have built the dark-colored lava shields of Nea and Palea Kameni inside the caldera.

Their last eruption was in 1950, and now only fumarolic activity, primarily inside the recently active craters, takes place.[1] GPS instruments registered renewed deformation around the caldera in 2011 and 2012.[7]

The huge Minoan eruption of Santorini in the 17th century BC may have inspired the legend of Atlantis.[8] It was rated 7, the highest score for a historical eruption, in the Smithsonian Global Volcanism Program's Volcanic Explosivity Index.[9]

Eruptive history

Following is a list of the major eruptive events of Santorini beginning with the catastrophic Minoan eruption, as noted by the Smithsonian National Museum of Natural History's Global Volcanism Program:[5]

Start date	Stop date	Characteristics of eruption
1610 BC ± 14 years ("Minoan eruption")	Unknown	Central vent eruption, regional fissure eruption, submarine eruption, explosive eruption, pyroclastic flows and pyroclastic surges, phreatic explosions, extensive physical damage, massive lava fountains and extensive lava flows, minor mudflows on the sea, megatsunamis, caldera collapse, fatalities, mass evacuation.
197 BC	Unknown	Central vent eruption, regional fissure eruption, submarine eruption, new island formation, explosive eruption.
Dec 31, 46 AD	Feb 1, 47 AD ± 30 days	Central vent eruption, regional fissure eruption, submarine eruption, new island formation, explosive eruption, lava flows, lava dome extrusion, tsunami.
Jul 15 726 AD ± 45 days	Unknown	Central vent eruption, regional fissure eruption, submarine eruption, new island formation, explosive eruption, lava flows, lava dome extrusion, damage.
1570	1573	Central vent eruption, regional fissure eruption, submarine eruption, new island formation, explosive eruption, lava flows, lava dome extrusion.
Sep. 27, 1650	Dec. 6, 1650	Flank (excentric) vent, regional fissure eruption, submarine eruption, new island formation, explosive eruption, lava flows, fatalities, damage, tsunami.
May 23, 1707	Sep. 14, 1711	Central vent eruption, regional fissure eruption, submarine eruption, new island formation, explosive eruption, lava flows, lava dome extrusion, damage.
Jan. 26, 1866	Oct. 15, 1870	Central vent eruption, regional fissure eruption, submarine eruption, new island formation, explosive eruption, lava flows, lava dome extrusion, fatalities, damage, evacuation.
Aug. 11, 1925	Mar. 17, 1928	Central vent eruption, regional fissure eruption, explosive eruption, phreatic explosions, lava flows, lava dome extrusion.
Aug. 20, 1939	Jul. 2, 1941 ± 1 day	Central vent eruption, regional fissure eruption, submarine eruption, explosive eruption, phreatic explosions, lava flows, lava dome extrusion, damage.
Jan. 10, 1950	Feb. 2, 1950	Central vent eruption, regional fissure eruption, submarine eruption, explosive eruption, phreatic explosions, lava flows, lava dome extrusion.

References

На других языках

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- [en] Santorini caldera

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[fr] Caldeira de Santorin

La caldeira de Santorin est une baie délimitée par les différentes îles de l'archipel de Santorin, constituée d'une caldeira submergée et cernée par des falaises. Cette caldeira s'est formée autour de 1600 av. J.-C. au cours de l'éruption minoenne, qui a vu la destruction d'une partie de l'ancienne île. Celle-ci comportait déjà une caldeira, plus petite ; ses vestiges constituent les îles actuelles de Santorin, Thirassía et Aspronissi.

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[ru] Санторин (вулкан)

Сантори́н (греч. Σαντορίνη) — кальдера на действующем щитовом вулкане на острове Тира в Эгейском море, образовавшаяся в результате извержения, которое привело к гибели эгейских городов и поселений на островах Крит, Тира и побережье Средиземного моря. Извержение датируется 1700—1600 годами до н. э. (по разным оценкам). По шкале вулканической активности извержение имело 7 баллов, что сопоставимо с извержением Тамбора и в 3 раза сильнее извержения Кракатау. Облако пепла простиралось на 200—1000 км. По распространённой версии, извержение, вызвавшее гигантское цунами высотой до 100 метров[2], уничтожило минойскую цивилизацию Крита. Существует гипотеза, что извержение легло в основу легенды об Атлантиде[3].

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