| A | B |
|---|
| caldera | a large circular depression, or basin, at the top of a volcano |
| cinder cone | a kind of volcano, usually steep-sloped, that is formed from layers of cinders, which are sticky bits of volcanic material |
| composite cone | a kind of volcano formed when explosive eruptions of sticky lava alternate with quieter eruptions of volcanic rock bits |
| hot spot | a place deep within Earth's mantle that is extremely hot and contains a chamber of magma |
| island arc | a chain of volcanoes formed from magma that rises as a result of an oceanic plate sinking into the mantle |
| lava | magma that flows out onto Earth's surface from a volcano |
| magma | the hot, molten rock deep inside Earth |
| rifting | the process by which magma rises to fill the gap between thwo plates that are moving apart |
| siesmometer | an instrument that detects and records Earth's movements |
| shield cone | a kind of volcanic cone that is large and gently sloped and that is formed when lava flows quietly from a crack in the Earth's crust |
| tiltmeter | an instrument that measures any change in the slope of an area |
| volcano | an opening in Earth's crust through which hot gases, rock fragments, and molten rock erupt |
