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
The size of volcanic islands usually ranges between 1 and 104 square kilometres (0.4 and 40 sq mi). [2] 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.
Many volcanic islands emerge from the deep abyss of the ocean, featuring rough or mountainous landscapes in their interiors and displaying a diverse array of summit elevations. Researches observed that the island will often be covered by dense tropical forest. The forests limit the use of the lands for settlement on many islands, therefore Communities, roads and houses were limited to develop along the coaster margin, as a result suffering from coastal hazards.[3] On larger islands rivers can flow, resulting in flood hazards and delivering sediment, which can dominate coastal morphology. Tall volcanic islands are often surrounded by protective fringing or barrier reefs, creating lagoons.[3]
A study focused on the vulnerability of volcanic islands to multi-risk natural hazards, which are expected to worsen due to climate change. These include not just volcanic eruptions, but also earthquakes, tsunamis, landslides, and severe weather events like hurricanes or typhoons. The unique geological and geographical characteristics of volcanic islands make them prone to these diverse hazards. The research highlighted the importance of implementing effective risk mitigation plans that include nature-based solutions to improve societal safety on these islands. These solutions involve leveraging natural processes and ecosystems to reduce hazard impacts. This can include the restoration of natural barriers like mangroves or coral reefs that protect against tsunamis and storm surges, or the maintenance of natural water catchments that can mitigate flood risks. [4]
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. Bibcode:1949GeoRv..39..425M. doi:10.2307/210643. JSTOR 210643.
- ^ Condie, Kent C. (2022-01-01), Condie, Kent C. (ed.), "Chapter 2 – The crust", Earth as an Evolving Planetary System (Fourth Edition), Academic Press, pp. 9–37, ISBN 978-0-12-819914-5, retrieved 2023-12-28
- ^ a b Velmurugan, Ayyam (2008-01-01), Sivaperuman, Chandrakasan; Velmurugan, Ayyam; Singh, Awnindra Kumar; Jaisankar, Iyyappan (eds.), "Chapter 1 – The Nature and Characters of Tropical Islands", Biodiversity and Climate Change Adaptation in Tropical Islands, Academic Press, pp. 3–30, ISBN 978-0-12-813064-3, retrieved 2023-12-28
- ^ López-Saavedra, Marta; Martí, Joan; Planagumà, Llorenç (2023). "How Effective Risk Assessment and Management Is the Key to Turning Volcanic Islands into a Source of Nature-Based Solutions". Land. 12 (3): 686. doi:10.3390/land12030686. ISSN 2073-445X.
External links
- Micronesian culture: High island and low island cultures at Britannica.com. Retrieved 2011-09-22.