| A | B |
|---|
| volcano | a mountain that forms when molten rock, called magma, is forced to the Earth's surface |
| lava | magma that flows onto the Earth's surface |
| pyroclastic material | rock fragments created by volcanic eruptions |
| shield volcano | built out of layers of lava from repeated nonexplosive eruptions |
| cinder cone volcano | small volcanic cones made entirely of pyroclastic material from moderately explosive eruptions |
| composite volcano | most common type of volcano; formed by explosive eruptions of pyroclastic material followed by quieter outpourings of lava |
| crater | funnel-shaped pit at the top of the central vent in most volcanoes |
| caldera | forms when a magma chamber that supplies material to a volcano empties and its roof collapses |
| rift | a deep crack that forms when tectonic plates separate |
| hot spot | places on the Earth's surface that are directly above colums of rising magma |
