Three Types of Volcanoes Repeated volcanic eruptions build volcanic mountains of three basic types, or shapes, depending on the nature of the materials deposited by the eruption. Lava flow upon lava flow slowly builds a broad, gently sloping volcanic shape that resembles a warrior's shield. Layers of tephra alternating with layers of viscous lava flows create steep-sided, often symmetrical cones that we think of as the classic volcano shape. Blown violently into the air, the erupting lava breaks apart into fragments called cinders . The fallen cinders accumulate into a cone around the volcano's central vent.
Cinder cones can form on the flanks of shield and stratovolcanoes.
In small groups, students build models of the three major types of volcanoes and see how a volcano's shape is related to the type of material it erupts. The lesson concludes with a discussion of how a volcano's shape is related to the nature of the material it erupts. A volcano is a circular or linear opening in the Earth's surface through which lava, rock fragments, ash , aerosols , and gases erupt. A volcano is also the landform, often a mountain, built from repeated eruptions. Introduce the concept that a volcano is both an opening in the Earth's surface through which magma erupts and a landform.