Volcanic Island Growth Circles

The diagram depicts the different stages of the development of a volcanic island. Overall, the volcanic island growth cycle has nine stages shown in the whole process, starting growing under the sea, exploding, and then finally sinking to become an underwater reef. To begin with, a mountain gradually forms beneath the surface of the sea in the first two stages, known as the 'preshield' and 'protoshield' stages. Hydro-explosions occur in the third or "explosive" phase, resulting in an ash cone. A great number of cinder cones then pile up on top of the volcano, forming a "shield. " By the time of the sixth and seventh phases, this shield erodes and subsides over time, forming reefs beneath the surface of the sea. Nevertheless, there may be continuing volcanic activity, allowing lava to flow out into the sea. After that, the original form of the volcano has vanished in the ‘coral atoll’ stage, and the whole structure sinks further under the sea during the last phase, called the ‘guyot’ stage.