| Metamorphic Rock | Metamorphic Rock - Rock, whether igneous, sedimentary, or metamorphic, that has been physically transformed due to heating or pressure. |
| Volcanism | The movement of melted earth material (magma) up through the Earth's crust and onto the Earth's surface as lava and tephra. |
| Tephra | Pulverized rock and pyroclastic materials (rock pieces) ejected violently during a volcanic eruption |
| Composite Volcano | This is the classic, steep, conical volcano made up of alternating
layers of lava
and tephra. |
| Shield Volcano | This is a volcano formed by less viscous (more fluid) lava which leads
to broad,
gradual (not steep), often symmetrical slopes. |
| Cinder Cone | Small volcanic hills which emit little lava, but rather are composed
mainly of tephra
material which forms a steep pile of debris. |
| Caldera | The collapsed summit or crater of a volcano. |