Volcanoes are fascinating geological features that act as windows into Earth's interior. They form when molten rock, called magma, finds a pathway from deep underground to the surface. To understand how volcanoes work, we need to look at Earth's structure, which consists of the crust, mantle, and core.
The volcanic process begins deep within Earth where intense heat and pressure melt solid rock into magma. This molten rock is less dense than the surrounding solid rock, causing it to rise toward the surface. The magma moves upward through cracks and weak spots in Earth's crust, driven by buoyancy forces.
As magma rises, it often collects in underground reservoirs called magma chambers. Here, dissolved gases like water vapor and carbon dioxide are kept under tremendous pressure. As the magma moves closer to the surface, the pressure decreases, allowing these gases to expand rapidly, building up enormous pressure that will eventually drive the volcanic eruption.
When the pressure from expanding gases and rising magma exceeds the strength of the overlying rock, a volcanic eruption occurs. Magma erupts through vents as lava, along with ash, volcanic gases, and rock fragments. Over time, repeated eruptions deposit layers of lava and ash around the vent, gradually building up the characteristic cone shape of a volcano.
To summarize how volcanoes work: they form when molten rock from deep within Earth finds pathways to the surface. Heat and pressure melt solid rock into magma, which rises due to its lower density. This magma collects in underground chambers where gas pressure builds until eruption occurs, releasing lava, ash, and gases that gradually build the volcano's cone shape through repeated eruptions.