Hawaii has many volcanoes some of which are called Mauna Loa and Kohala. When the magma reaches the top of a volcano it erupts as lava which is ash and volcanic rocks. After each eruption lava builds up around it. There are 4 main types of volcanoes. Cinder Cone Volcanoes, Stratovolcanoes, Shield Volcanoes, and Lava Domes. Maunaloa, Kilauea, and loihi are the three active volcanoes in Hawaii.