A volcano is a vent in the Earth's crust through which magma, gases, and rock fragments are ejected. This geological phenomenon is primarily driven by the movement of tectonic plates, where the interaction between plates can cause pressure build-up and the ascent of molten material from the planet's mantle. Magma, which is chemically distinct from lava (the term used for magma once it reaches the surface), solidifies as it exits the vent, forming various cone shapes depending on the viscosity of the erupted material. The process involves volatile gases escaping the magma body, which drives the pressure and leads to the eruption of pyroclastic flows, ash clouds, and streams of highly heated material.