| A | B |
|---|
| volcano | A mountain formed from molten rock called magma. |
| lava | Magma that flows onto the surface of the earth. |
| magma | Molten rock inside the Earth. |
| pyroclastic material | Rock fragments created by explosive volcanoes. |
| shield volcanoes | Volcanoes built out of layers of lava from nonexplosive volcanoes. |
| cinder cone volcanoes | Small volcanic cones made entirely of pyroclastic material. |
| composite volcanoes | Also called stratovolcanoes and are made of alternating layers of lava and pyroclastic material. |
| crater | A funnel-shaped pit at the top of the central vent. |
| caldera | Created with a magma chamber empties and the roof collapses. |
| hot spots | Places on the earth's surface that are directly above columns of rising magma. |
| rift | A deep crack that forms at a divergent boundary. |
| vent | Holes in the earth's crust through which magma rises, |
| extinct volcanoes | Volcanoes that have not erupted in recorded history and probably never will. |
| dormant volcanoes | Volcanoes that are not currently erupting but have done so at some time in recorded history. |
| active volcanoes | Volcanoes that are erupting or show signs of erupting. |
