Magma is the essential precursor to all volcanic activity, located within the Earth’s lithosphere or asthenosphere. It is a complex mixture of molten silicate rock and dissolved volatiles like water vapor and carbon dioxide. Magma originates from the partial melting of the mantle through processes like decompression or flux melting. Because it is less dense than the surrounding solid rock, it tends to rise toward the surface. The term “magma” is strictly reserved for the underground state; once it erupts through a vent, it becomes “lava,” marking a change in both location and chemical gas content.