volcanoes

Vo l c an o esViolentPlanet



Fire from beneath A volcano is a vent or an opening on the earth’s surface through which molten rock, or magma, comes out. A mountain that is formed by the accumu- lation of molten rock and ashes is also called a volcano.

Volcanoe’s Violent Planet Earthy layers Diagram-1: Earthy layers The earth can be divided into three layers – crust, mantle A crusty affair and core. The crust forms the ground we walk on, while The earth’s crust does not exist as one the core is the innermost huge layer. It is divided into several layer of the earth. The core is smaller pieces called tectonic plates. composed of metals like The plates beneath the ocean are called iron and nickel. The middle oceanic plates, and those that form the layer is called mantle. The land are called continental plates. All these temperature in the mantle so pieces fit together like a jigsaw puzzle to high that it melts even rocks! It form the crust. These plates float on the is this molten rock that comes mantle, which consists of molten rock, to the surface during a volcanic and therefore are always moving. It is this eruption. movement that causes earthquakes and volcanic eruptions.

Strip Feature Diagram-3: Strip Features Most volcanoes are caused by subduction. In this process, one plate is of volcano. pushed beneath the other, as both of them collide. The sudden movement and the friction produce a huge amount of heat, which melts parts of the plate that slipped below. The magma, or molten rocks, thus formed rise and collect just below the surface cre- ating mag- ma cham- bers. When the pressure inside the chambers becomes very high, the magma is ejected out into the surface causing a volcanic eruption. Diagram-2: Tectonic plates Layers Volcanoes are usually found on the boundaries of plates. Sometimes, they are also formed in other parts of the plate over regions known as hotspots. A hotspot is a fixed area in the mantle where a large amount of magma is produced. This magma comes out through tiny cracks on the earth’s crust to form volcanoes. The hotspot stays in one place, as the plates above keep moving causing a string of volcanoes to formed. The Hawaiian Islands were formed in this manner 2