Surtseyan eruption
A Surtseyan eruption is a type of volcanic eruption that takes place in shallow seas or lakes. It is named after the island of Surtsey off the southern coast of Iceland.[1]
These eruptions are commonly phreatomagmatic eruptions, representing violent explosions caused by rising basaltic or andesitic magma coming into contact with abundant, shallow groundwater or surface water. Tuff rings, pyroclastic cones of primarily ash, are built by explosive disruption of rapidly cooled magma.
Characteristics
Although similar in nature to phreatomagmatic eruptions, there are several specific characteristics:[2]
- Physical nature of magma: viscous; basaltic.
- 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 flows; lavas 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, United States, 1796
Fire Island - Alaska, United States, 1796
Anak Krakatau - Sunda Strait, Indonesia, 1927–1930 (with smaller eruptions continuing today) Resuming since December 23, 2018
Shōwa Iōjima - Iōjima, Kagoshima, Japan, 1934
Capelinhos - Faial Island, Azores, 1957–1958
Surtsey - Iceland, 1963
Jólnir - Iceland, 1966
Taal Volcano - Batangas, The Philippines (last erupted 1977)
Zubair Group - Yemen, 2011–2012
El Hierro - Canary Islands, 2011–2012 (see 2011–12 El Hierro eruption)
References
^ Island Building Events
^ Surtseyan Eruptions Archived 2010-04-29 at the Wayback Machine.