islands formed by volcanoes
Volcanic islands are formed by volcanic activity on the seabed, often near the boundaries of the tectonic plates that form Earthâs crust.Where two plates pull apart, lava erupts to form an undersea ridge. Layers of lava build up until a ridge breaks the seaâs surface to form an island.olcanic islands are formed by volcanic activity on the seabed, often near the boundaries of the tectonic plates that form Earthâs crust.