What causes volcanic eruptions?

Volcanic eruptions occur when magma from beneath the Earth’s crust escapes to the surface due to pressure buildup. The Earth’s crust is made up of tectonic plates that float on the semi-fluid mantle beneath them. When these plates move, they can create faults and cracks, allowing magma to rise. As magma moves through the crust and escapes through volcanic vents, it erupts, often violently, sending ash, gases, and lava into the atmosphere. The nature of the eruption depends on the type of magma and the amount of gas trapped within it.