Kolumbo () is an active

submarine volcano Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges ...

in the

Aegean Sea The Aegean Sea is an elongated embayment of the Mediterranean Sea between Europe and Asia. It is located between the Balkans and Anatolia, and covers an area of some . In the north, the Aegean is connected to the Marmara Sea, which in turn con ...

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

, about 8 km northeast of Cape Kolumbo,

Santorini Santorini (, ), officially Thira (, ) or Thera, is a Greek island in the southern Aegean Sea, about southeast from the mainland. It is the largest island of a small, circular archipelago formed by the Santorini caldera. It is the southern ...

island. The largest of a line of about twenty submarine volcanic cones extending to the northeast from Santorini, it is about 3 km in diameter with a crater 1.5 km across. It was first noticed by humans when it breached the sea surface in 1649–1650. The

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, Education center, education and Research institute, research centers, created by the Federal government of the United States, U.S. government "for the increase a ...

Global Volcanism Program The Smithsonian Institution's Global Volcanism Program (GVP) documents Earth's volcanoes and their eruptive history during the Quaternary Period of Earth's geologic history, with particular emphasis on volcanic activity during the Holocene Epoc ...

treats it as part of the Santorini volcano, though at least one source maintains that it is a separate magmatic system.

History

An eruption in 1650, which occurred when the accumulating cone reached the surface, sent

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

s across the sea surface to the shores and slopes of Santorini, where about seventy people and many animals died. A small ring of white

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ...

that formed was rapidly eroded away by wave action. The volcano collapsed into its

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

, triggering a

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

that caused damage on nearby islands up to 150 km distant. The highest parts of the crater rim are now about 10 m below sea level. In 2006, sea floor pyroclastic deposits from the two Aegean explosions were explored, sampled and mapped by an expedition by NOAA Ocean Explorer, equipped with ROV robotics. The crater floor, averaging about 505 m below the sea surface, is marked in its northeast area by a field of

hydrothermal vent Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hot ...

s and covered by a thick

bacterial Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

community, the 2006 NOAA expedition discovered. Superheated (measured as hot as 224 °C) metal-enriched water issuing from the vents has built chimneys of polymetallic sulfide/sulfates to a maximum height of 4 m, apparently accumulated since the 1650 event. The 2006 expedition initiated new seismic air-gun techniques in order to determine the volume and distribution of the submarine volcanic deposit of pumice and ash on the sea floor around Santorini, which has been studied extensively since 1975. Revised, more accurate estimates of the total

dense rock equivalent Dense-rock equivalent (DRE) is a volcanologic calculation used to estimate volcanic eruption volume. One of the widely accepted measures of the size of a historic or prehistoric eruption is the volume of magma ejected as pumice and volcanic ash, k ...

volume of the Minoan event(s), consisting of pyroclastic sea floor deposits, distal ash fallout and

ignimbrite Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrou ...

s on the island of Santorini, is likely about 60 km³, a greatly increased estimate, comparable to the largest historic explosion,

Mount Tambora Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, it was formed by the active subduction zones beneath it. Before the 1815 eruption, its elevation reached m ...

1815; the increased estimate affects the size of the ensuing

as it has been widely modeled. In October 2022 it was announced that a previously undetected magma chamber had been discovered approximately 2 to 4 km below sea level in the Kolumbo underwater volcano. Scientists had determined that it is gradually filling with melt. Although an eruption is not imminent, it does pose a threat which has prompted them to recommend real-time monitoring of the volcano.

Notes

References

NOAA Ocean Explorer: Thera 2006 Expedition Summary
*

Ferdinand André Fouqué Ferdinand André Fouqué (21 June 1828 – 7 March 1904) was a French geologist and petrologist. He was born at Mortain, in the Manche ''département''. At the age of twenty-one he entered the École Normale Supérieure in Paris, and from 1853 ...

, ''Santorin et ses éruptions'' (Paris: Masson) 1879. *Haraldur Sigurdsson, S. Carey, C. Mandeville, 1990. "Assessment of mass, dynamics and environmental effects of the Minoan eruption of the Santorini volcano" in ''Thera and the Aegean World III: Proceedings of the Third Thera Conference'', vol II, pp 100–112. *Haraldur Sigurdsson and S. Carey "Marine investigations of Greece's Santorini volcanic field"
on-line text
Sigurdsson and Carey's revised estimate.

External links

{{commonscat-inline Minoan geography Calderas of Greece Volcanoes of Greece Volcanoes of the Aegean Submarine calderas Active volcanoes VEI-4 volcanoes 17th-century volcanic events Landforms of Thira (regional unit) Landforms of the South Aegean Ephemeral islands Former islands from the last glacial maximum

History

See also

Notes

References

Further reading

External links