How do volcanoes create new land?

Explore how lava cools into rock and how volcanic islands and landscapes form.

The short answer

When molten rock reaches the surface, it's called lava. As lava cools and solidifies, it forms new rock. Repeated eruptions can build layers of rock into mountains, expand coastlines, and even create islands.

Where does the new land come from?

It comes from molten material within Earth. Some volcanoes form near boundaries between tectonic plates; others form over hot spots. Over many eruptions, the accumulated rock can rise above sea level.

The surprising connection: life on bare rock

New volcanic rock may initially have little or no soil. Weathering, microbes, windblown material, and pioneering plants can gradually help create conditions for more complex ecosystems.

Try it

Look at photographs of a young volcanic landscape and an older one. What clues show how vegetation and soil developed over time?