Part 9: Volcanism & Magmatism

Fire from Below

Volcanism is the surface expression of magma generation deep within the Earth. Most volcanic activity concentrates at plate boundaries—mid-ocean ridges and subduction zones—but hotspot volcanism occurs within plate interiors. Understanding magma genesis, ascent, and eruption style is critical for hazard assessment and resource exploration.

~1,500

Active Volcanoes

~80%

At Plate Boundaries

700–1300°C

Magma Temperature

Topics in This Part