Volcanic island
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Geologically, a volcanic island is an island of volcanic origin. The term high island can be used to distinguish such islands from low islands, which are formed from sedimentation or the uplifting of coral reefs[1] (which have often formed on sunken volcanos).
Definition and origin
There are a number of volcanic islands that rise no more than 1 metre (3 ft 3 in) above sea level, often classified as "islets or rocks", while some low islands, such as Banaba, Henderson Island, Makatea, Nauru, and Niue, as uplifted coral islands, rise over 50 metres (160 ft) above sea level.
The two types of islands are often found in proximity to each other, especially among the islands of the South Pacific Ocean, where low islands are found on the fringing reefs that surround most volcanic islands. Volcanic islands normally arise above a hotspot.
Habitability
Volcanic islands above a certain size usually have fresh groundwater, while low islands often do not, so volcanic islands are more likely to be habitable.
See also
- Archipelagic apron – Fan-shaped gently sloping region of sea floor found around oceanic islands
- Atoll – Ring-shaped coral reef
- Canary Islands – Spanish archipelago and region in the Atlantic Ocean
- Galápagos Islands – Ecuadorian archipelago and protected area
- Guyot – Isolated, flat-topped underwater volcano mountain
- Krakatoa Archipelago – Archipelago in the Sunda Strait, Indonesia
- Seamount – Mountain rising from the ocean seafloor that does not reach to the water's surface
- Submarine landslide – Landslides that transport sediment across the continental shelf and into the deep ocean
- Volcanic arc – Chain of volcanoes formed above a subducting plate
References
- ^ Murphy, Raymond E. (July 1949). ""High" and "Low" Islands in the Eastern Carolines". Geographical Review. 39 (3). American Geographical Society: 425–439. doi:10.2307/210643. JSTOR 210643.
External links
- Micronesian culture: High island and low island cultures at Britannica.com. Retrieved 2011-09-22.