Use the diagram provided to compare and contrast the three principal types of volcanoes. Place the phrases corresponding to features unique to either group in the boxes shown. Place them in other boxes if the phrase is common to more than one volcano type. vent gases associated with subduction zones found in Hawaii principal rock type—andesite example: Mount Hood, Oregon main product-ava have a triangular shape in profile | high-silica magma found in continental US and Alaska composition mainly tephra smallest volcanoes low silica magma form chains of volcanic islands explosive eruptions magma from partial melting of mantle example: Mauna Loa principal rock type-basalt mild eruptions largest volcanoes intermediate silica magma pose greatest hazards Stratovolcanoes Cinder Cones Shield Volcanoes All three Types. Stratovolcanoes and Cinder Cones Strato- and Shield Volcanoes