| A | B |
|---|
| volcano | a crack or weak spot in the Earth's crust where magma comes up to the surface |
| magma | the molten mixture of rocks and gases in the Earth's mantle |
| lava | molten material that reaches the Earth's surface |
| Ring of Fire | a major belt of volcanoes that forms a ring around the Pacific Ocean |
| island arc | a string of islands formed by a volcano at a plate boundary |
| hot spot | an area where magma melts through the Earth's crust to form a volcano that is not on a plate boundary |
| magma chamber | the pocket beneath a volcano where magma collects |
| pipe | a long, thin tube that carries magma from the magma chamber to the Earth's surface |
| vent | the opening where magma leaves a volcano |
| lava flow | a river of lava that flows out of the vent and down the side of a volcano |
| pyroclastic flow | an explosive eruption that throws out ash, rocks, hot gases, and causes huge landslides and mudflows |
| active | a live volcano that is erupting or is showing signs of erupting |
| dormant | a sleeping volcano that is not erupting now but may erupt again in the future |
| extinct | a dead volcano that will most likely never erupt again |
| geyser | a fountain of hot water and steam that erupts from the ground because of a body of magma just under the Earth's surface |
