Volcanism

Volcanism is the set of processes related to the ascent, accumulation, and expulsion of magma from the Earth’s interior to the surface.

It includes:

• Volcanic eruptions.
• Lava flow.
• Volcanic gases.
• Ash.
• Formation of volcanoes and igneous rocks.

How it occurs

Deep within the Earth, some rocks partially melt and form magma.

Since this magma is less dense, it rises through fractures and may become trapped at depth; it may crystallize slowly or reach the surface and cause eruptions.

Types of volcanism

• Effusive: the lava is fluid, and eruptions are relatively calm.
• Explosive: the magma is viscous, contains large amounts of gas, and the eruptions are violent.