Learn the parts of a volcano, types of eruptions, and famous volcanoes
A volcano is an opening in Earth's crust where molten rock, ash, and gases escape from below the surface. When a volcano erupts, magma rises through the vent and flows out as lava. Volcanoes are found on every continent and even under the ocean. They form at the boundaries of tectonic plates or over hot spots in Earth's mantle.
There are three main types of volcanoes. Shield volcanoes like Mauna Loa in Hawaii have gentle slopes and produce slow-flowing lava. Stratovolcanoes (also called composite volcanoes) like Mount Fuji and Mount St. Helens are tall and steep with explosive eruptions. Cinder cone volcanoes are the smallest type, built from fragments of lava ejected from a single vent.
Volcanoes are classified as active, dormant, or extinct. Active volcanoes have erupted recently or show signs of activity. Dormant volcanoes have not erupted in a long time but could erupt again. Extinct volcanoes are not expected to erupt ever again. The Ring of Fire around the Pacific Ocean contains about 75 percent of the world's active volcanoes.
Explore different volcano types, learn how eruptions happen, and discover famous volcanoes from around the world in this interactive tool. Aligned with elementary and middle school Earth science standards.
Last reviewed: April 2026