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LESSON 4 · Fire Mountains: Volcanoes

Born from the Deep

Volcanic islands begin on the ocean floor when magma erupts from vents beneath the waves. The lava cools instantly on contact with seawater, building a mound of pillow-shaped rocks called pillow lava. Layer after layer accumulates over thousands of years until the growing seamount breaks the ocean surface.

The moment lava meets air instead of water, everything changes. The eruption becomes violent as steam explosions shatter rock into fine ash. The island grows through cycles of eruption and collapse until it stabilizes.