Why do volcanoes erupt?

Reader

The Earth is hot inside. That heat is trying to get out. One of the principal ways that the Earth loses its heat is via volcanic eruptions, especially along the Mid-Ocean Ridge and Hot Spot volcanoes. As magma moves closer to the surface, gas appear in the magma. The magma becomes less dense, and so it rises to the surface, and an eruption results. And so, volcanoes erupt because the Earth is cooling. The immediate process near the surface is the appearance of gas in magma.

Sincerely,
John Dvorak

Other Categories Other Questions
To VolcanoWorld