April 9, 2026

Bade Soybakış

Işıkkent High School

11th Grade

Islands are quite interesting; they have been formed far from the main land and rose above the sea level. How can a piece of land be formed independently? There is more than one factor forming islands, though we are going to examine how volcanoes create islands.

Volcanic islands are formed by submarine volcanoes, volcanoes that are under the sea level. Submarine volcanoes erupt underwater, relatively passively compared to volcanoes on land because of the pressure of the ocean on the rising magma. This leads the magma to accumulate underwater and form an island. It is important to note that they do not erupt instantly above sea level and create an island. It takes a long period of time to rise above sea level, expand, and eventually create an island. However, the explanation of how volcanoes create islands is not that simple. We have to know about tectonic plates.

Tectonic plates are irregularly shaped giant rocks, composing the lithosphere of the Earth. Tectonic plates interact with each other, moving towards, away from, or perpendicular to each other due to the convection of magma inside the mantle. These movements allow magma to emerge to the surface, eventually creating new volcanoes. Constructive and destructive boundaries with hot spots of the tectonic plates are responsible for creating new volcanoes.

Constructive boundaries are where tectonic plates move away from each other, generating empty spaces where magma can flow and form new crust. At destructive boundaries, tectonic plates move towards each other. When two plates move towards each other, one of the plates subducts underneath the other. The magma wells up and emerges from the boundary as the subducted plate lifts the magma towards the surface. In both scenarios, the movements should occur from two oceanic plates. Magma emerges and creates seamounts, which can transform into a volcano or directly into a submarine volcano. As the magma accumulates from volcanic eruptions, it can reach above sea level. When it does, the magma will expand over sea level and eventually form an island. Iceland is a great example of places where volcanoes formed by constructive boundaries generate islands. There are more than 100 volcanoes, 30 of them being active today. The place is surrounded by a myriad of islands.

Furthermore, volcanoes can form far from the plate boundaries. This is called hotspot volcanism, in which magma rises upwards to the surface of the crust in the middle of the tectonic plate. These hot spots forge volcanoes, and if they are located on an oceanic plate, they can create an island as magma cools down and piles up above the sea level. The Hawaii Islands are the best examples of how hot-spot volcanoes result in islands. They are formed by a hot spot in the middle of the Pacific Plate. The Pacific Plate is continuously moving towards the northwest. As the plate moves over the hot spot, this movement creates a chain of islands.

In conclusion, volcanoes have a crucial role in the formation of new islands thanks to convectional flows in the mantle and tectonic plates. As oceanic plates move towards or move away from each other, hot spots' magma rises to the surface, forming submarine volcanoes. By eruptions of submarine volcanoes, magma accumulates, and over a long period of time, an island is formed.