Question

How do volcanoes make land?

Answer 1

Magma that cools underground forms intrusions (Figure below). Usually this magma is very viscous felsic magma. This magma does not rise easily and so cools slowly underground. Intrusions become land formations if they are exposed at the surface by uplift and erosion.

Answer 2

Lava erupted from volcanoes and magma trapped below the volcanoes underground will eventually crystallize to form new rock. In some areas, this new rock can grow outwards from the coastline or upward from the seafloor to form new land.