| A | B |
|---|
| magma chamber | the pocket beneath a volcano where magma collects |
| geothermal energy | energy from water or steam that has been heated by magma |
| vent | the opening through which molten rock and gas leave a volcano |
| lava flow | the area covered by lava as it pours out of a volcano's vent |
| crater | a bowl-shaped area that forms around a volcano's central opening |
| silica | a material that is formed from the elements oxygen and silicon; it is found in magma |
| pahoehoe | a hot, fast-moving type of lava that hardens to form smooth, ropelike coils |
| aa | a slow-moving type of lava that hardens to form rough chunks; it is cooler than pahoehoe |
| pyroclastic flow | the expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption |
| active | this describes a volcano that is erupting or has shown signs of erupting in the near future |
| dormant | this describes a volcano that does not show signs of erupting in the near future |
| extinct | this describes a volcano that is unlikely to erupt again |
| hot spring | a pool formed by groundwater that has risen to the surface after being heated by a nearby body of magma |
| geyser | a fountain of water and steam that builds up pressure underground and erupts at regular intervals |
| pipe | a long tube through which magma moves from the magma chamber to Earth's surface |
