Volcanic Islands: What are they, how they form and examples

The volcanic islands are a portion of isolated territory that are surrounded by water. They are very peculiar geological structures, of short life cycle, which are usually found in oceanic basins and lakes.

Generally, They are formed from the eruption of submarine volcanoesalthough on the planet Earth there are more than one million of them, only a few are able to emerge and form islands on the surface. Submarine volcanic eruptions accumulate lava layers and volcanic material, which sometimes emerge from the water surface. When this occurs, the lava solidifies and forms these extraordinary islands.

We recommend this article about underwater volcanoes: what they are, how they are formed and how many are there.

Volcanic island formation processes

The formation of the volcanic islands originates from volcanism from different processes:

• Extensive processes: They form islands that arise between two tectonic plaques creating a centeroCeanic dorsal that reaches the surface.
• Compressive processes: They occur when two tectonic plates collide, and one immerses itself under the other in a subduction process. The subduction plate is increasingly pressure, causing Magma’s rise to the surface, forming a series of volcanoes. These volcanoes can form islands known as “island arch.”
• Hot point: The theory of the hot point or “Hot Spot” is used to explain the formation of volcanoes in places where the oceanic crust is not tectonically active. The islands are formed by the magmatism caused by a thermal anomaly of the mantle or hot point, followed by a fracture in the cortex, so the magma would ascend by these causing the underwater volcano. This theory is evidenced in Hawaii, since its volcanoes are older the more they move away from the hot point. Something similar occurs in the Canary Islands, one of the volcanic islands in Spain more famous, where the archipelago has been built from this to west, presenting different geological ages.

Training stages

Although there are different processes that give rise to their formation, all volcanic islands go through similar stages:

1. Submarine volcano formation: The magma under pressure ascends, creating the so -called magmatic chambers inside or under the cortex. The cracks present in the crust rocks provide an exit for intense pressure, and the eruption occurs. Elements such as smoke, water vapor, gases, ashes, rocks and lava are released to the atmosphere. The rocks accumulated in the magmatic chamber slowly cool, forming plutonic rocks. When molten rocks come into contact with water, they solidify rapidly. The base of the island is constituted by plutonic and volcanic rocks, which are mixed with marine sediments.
2. Subaéreo Vulcanism: When the eruptions reach the water level, the rise volcanism appears where large amounts of material are emitted as the island is formed on the submarine building, a process that takes millions of years.
3. Calm period: After the previous phase, a period of calm occurs where erosion takes place and form ravines that extend from the center out of the island. Some experts call this “erosive disagreement” stage.
4. Rejuvenation: In the volcanic islands there may be a subsequent stage of rejuvenation in which there are new phases of eruptions, explosive, with a great diversity of materials emitted. While the cause of this process is unknown, it may be related to the fact that the lithosphere performs a kind of “rebound” after being oppressed, producing the fusion and generation of magma.
5. Disappearance: After a long time, the islands can disappear under the sea because of the different erosive processes.

Here you will find more information about magma: what is, guys, where it is and how it is formed.

Hawaii is an archipelago belonging to the United States that is made up of 18 volcanic islands and atolls. It is composed of several volcanoes, including: Kilauea (the most active in the world), Mauna Loa, Mauna Kea, Hulakai and Kohala. Did you know that it forms a hot biodiversity point and that it is the only state in the United States that has a tropical jungle?

All the Canary Islands are volcanic, make up a Spanish autonomous community and are located in northwest Africa. The archipelago is formed by 8 islands, 5 islets and 8 roques. The 8 islands are Iron, La Gomera, La Palma and Tenerife (province of Santa Cruz de Tenerife) and La Graciosa, Fuerteventura, Gran Canaria and Lanzarote (Province of Las Palmas). In these islands There are 33 volcanoes And if you wonder how many volcanoes there are in Gran Canaria the answer is 10, since it is the island with the greatest amount of volcanoes.

You may be interested in this article about the Flora and Fauna of the Canary Islands.

Famous for its archaeological sites, Easter Island belonging to Chile is located in Polynesia in the Eastern Pacific. In it are the well -known stone statues called Moáis, which were sculpted by the former Rapa Nui civilization. Easter Island is of volcanic origin and is composed of three main volcanoes: Terevaka, Poike and Rano Kau.

Located a few kilometers from Iceland, Sortsey island is part of the underwater volcanic system of clothing that is part of the Mesoatlántic dorsal. It consists of 18 islands and numerous reefs. This formed by a volcano which has a diameter of 2.9 km and an area of ​​13.2 km². Currently, it has a height of 285 meters, of which 130 of them are under the sea.

Java is an island of Indonesia (one of the most densely populated in the world), which has volcanic origin and has a Great concentration of active volcanoes. Monte Merapi, Semeru and Kelut are the most active volcanoes on the island. Java stands out for his tourist sites and contains Yakarta, the capital of Indonesia.

Now that you know more depth the volcanic islands, do not miss these other articles on the types of volcanoes and what are ocean dorsal.

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