A Surtseyan eruption is an explosive style of volcanic eruption that takes place in shallow

sea The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...

s or

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

s when rapidly rising and fragmenting hot

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

interacts explosively with water and with water-steam-

tephra Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they re ...

slurries. The eruption style is named after an eruption off the southern coast of

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...

in 1963 that caused the emergence of a new volcanic island,

Surtsey Surtsey (" Surtr's island" in Icelandic, ) is a volcanic island located in the Vestmannaeyjar archipelago off the southern coast of Iceland. At Surtsey is the southernmost point of Iceland. It was formed in a volcanic eruption which began ...

. Surtseyan eruptions are hydromagmatic eruptions, in that they are violently explosive as a result of vigorous interaction between rising magma and lake or sea water. The magma is commonly basaltic and fragments into small

pyroclast Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they rem ...

s (known as ' ash' and ' lapilli'), and these accumulate around the crater to form a small cone or ring-shaped heap. Volcanoes of this type are known as '

tuff cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...

s' and '

tuff ring Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions cont ...

s' because the volcanic ash of which they are made soon solidifies by chemical reaction into a hard rock known as '

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock ...

'. Surtseyan eruptions are characteristically unsteady, with phases of rapid repeated short, violent explosions separated by more quiescent phases dominated by steam generation and condensation. Ash and lapilli are emplaced by ash fall (frequently moist or wet), and by short-duration,

pyroclastic density current 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 bu ...

s. The resultant deposits are characteristically well bedded with abundant evidence for moist conditions (e.g. ash aggregates, vesiculated ash layers, and soft-state deformed layers). Much of the wet tephra repeatedly slumps back down into the volcano's crater to be re-ejected by further watery explosions.

Characteristics

Although similar in nature to

phreatomagmatic eruption Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions cont ...

s, there are several specific characteristics: *Physical nature of magma:

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

ic. *Character of explosive activity: violent ejection of solid, warm fragments of new magma; continuous or rhythmic explosions; base surges. *Nature of effusive activity: short, locally pillowed,

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

flows (which may be rare). *Nature of dominant ejecta: lithic, blocks and ash; often accretionary lapilli; spatter, fusiform bombs and lapilli absent. *Structures built around vent: tuff rings

Examples of Surtseyan eruptions

* Bogoslof Island -

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...

, United States, 1796 *

Fire Island Fire Island is the large center island of the outer barrier islands parallel to the South Shore of Long Island, in the U.S. state of New York. Occasionally, the name is used to refer collectively to not only the central island, but also Lo ...

, United States, 1796 *

Graham Island Graham Island () is the largest island in the Haida Gwaii archipelago (previously known as the Queen Charlotte Islands), lying off the mainland coast of British Columbia, Canada. It is separated by the narrow Skidegate Channel from the other pr ...

Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

, 1831 *

Anak Krakatau Anak Krakatoa ( id, Anak Krakatau)English translation and common name: ''Child of Krakatoa'' is a volcanic island in Indonesia. On 29 December 1927, Anak Krakatoa first emerged from the caldera formed in 1883 by the explosive volcanic eruption ...

- Sunda Strait,

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

, 1927–1930 (with smaller eruptions continuing today) - further Surtseyan eruptions took place following the December 2018 eruption which left large sections of the volcano underwater *

Shōwa Iōjima , also known as , is one of the Satsunan Islands, usually classed with the Ōsumi Islands, belonging to Kagoshima Prefecture, Japan. A deserted volcanic island, it is located just off the northern shore of Iōjima, Kagoshima. Geography Shō ...

- Iōjima, Kagoshima, Japan, 1934 *

Capelinhos The Capelinhos (from Capelo + ''-inhos'' diminutive, which literally means "little cape") is a monogenetic volcano located on the western coast of Faial Island in the Azores. It is part of the larger volcanic complex of Capelo, which includes 20 sc ...

Faial Island Faial Island (), also known in English as Fayal, is a Portuguese island of the Central Group (Portuguese: ''Grupo Central'') of the Azores. The Capelinhos Volcano, the westernmost point of the island, may be considered the westernmost point of ...

Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

, 1957–1958 *

, 1963 *

Jólnir Jólnir () was formerly a volcanic island south of Iceland. It was a former vent of Surtsey, along with Syrtlingur and Surtla. It emerged from the ocean as a result of active plate tectonics between December, 1965 and July, 1966. Oceanic erosion ...

, 1966 * Taal Volcano -

Batangas Batangas, officially the Province of Batangas ( tl, Lalawigan ng Batangas ), is a province in the Philippines located in the Calabarzon region on Luzon. Its capital is the city of Batangas, and is bordered by the provinces of Cavite and La ...

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

(last erupted in

2021 File:2021 collage V2.png, From top left, clockwise: the James Webb Space Telescope was launched in 2021; Protesters in Yangon, Myanmar following the coup d'état; A civil demonstration against the October 2021 coup in Sudan; Crowd shortly after t ...

) * Zubair Group -

Yemen Yemen (; ar, ٱلْيَمَن, al-Yaman), officially the Republic of Yemen,, ) is a country in Western Asia. It is situated on the southern end of the Arabian Peninsula, and borders Saudi Arabia to the Saudi Arabia–Yemen border, north and ...

, 2011–2012 *

El Hierro El Hierro, nicknamed ''Isla del Meridiano'' (the "Meridian Island"), is the second-smallest and farthest-south and -west of the Canary Islands (an autonomous community of Spain), in the Atlantic Ocean off the coast of Africa, with a populatio ...

- Canary Islands, 2011–2012 (see 2011–12 El Hierro eruption) *

Fukutoku-Okanoba is a submarine volcano that is part of the Volcano Islands in the Bonin Islands of Japan. It is located northeast of the island of South Iwo Jima. Geography The volcano is part of a larger elongated submarine volcano with two peaks and with ...

Bonin Islands The Bonin Islands, also known as the , are an archipelago of over 30 subtropical and tropical islands, some directly south of Tokyo, Japan and northwest of Guam. The name "Bonin Islands" comes from the Japanese word ''bunin'' (an archaic read ...

, Japan, 2021 * Hunga Tonga-Hunga Ha'apai,

Tonga Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...

, 2021—2022 (see 2022 Hunga Tonga–Hunga Ha'apai eruption and tsunami)

References

Kokelaar, B.P (1983) The Mechanisms of Surtseyan volcanism. Journal of the Geological Society, London.140, 939–944. {{Types of volcanic eruptions Volcanic eruption types