Illustration showing different types of volcano and eruption. At centre is a stratovolcano that has an active secondary vent. It is undergoing an explosive eruption, releasing ash and pyroclastic material as well as lava. At centre left is a cinder cone volcano and at top left is a shield volcano. The magma in the shield volcano is more viscous and flows steadily from the volcano spreading along the ground. The volcanoes at right are undergoing steam-blast eruptions, where the magma encounters water, creating explosive steam.