(Holt Science and Technology Earth Science pg. 250-265)There is three types of volcanoes cinder cone, shield, and composite. The two types of eruptions are explosive and nonexplosive. Lava can travel as slow as not moving or as fast as 37.2823 miles per hour. A volcano is a vent or fissure in the Earth's surface through which magma and gases are expelled. The four types of lava are Aa, Pahoehoe, Blocky, and pillow. The four types of pyroclastic material are Lapilli, Volcanic Ash, Volcanic Bombs, and Volcanic Blocks. A caldera is a large circular indent that forms when the magma chamber below a volcano partly empties and causes the ground on top of the volcano to sink. A crater is a funnel shaped pit close to the top of a volcano.