(Fig. 2.3) Structure of a Volcano.

     A volcano constitutes a vent, a pipe, a crater, and a cone.

     The vent is an opening at the Earth's surface.

     The pipe is a passageway in the volcano in which the magma rises through to the surface during an eruption.

     The crater is a bowl-shaped depression at the top of the volcano where volcanic materials like, ash, lava, and other pyroclastic materials are released.

     Solidified lava, ashes, and cinder form the cone. Layers of lava, alternate with layers of ash to build the steep sided cone higher and higher.