| A | B |
|---|
| volcano | is a weak spot in the crust where molten material from the mantle comes to the surface |
| magma | molten mixture of rock-forming materials, gases and water |
| ring of fire | formed by the many volcanoes that rim the pacific ocean |
| island arc | string of islands created at the boundary where two oceanic plates collide |
| hot spots | an area where magma from deep within the mantle melts through the crust above it. |
| magma chamber | the pocket beneath a volcano where magma collects |
| pipe | a long tube that connects the magma chamber to earth's surface |
| vent | opening in the volcano |
| silica | material formed from oxygen and silicon |
| pahoehoe | hot, fast-moving lava |
| aa | cooler, slower moving lava |
| pyroclastic flow | occurs when an eruption hurls our ash, cinders and bombs in an explosive eruption |
| active volcano | a volcano that is erupting or has shown signs that it may erupt in the future |
| dormant volcano | a volcano that is not active now but may become active again in the future |
| extinct volcano | a volcano that is unlikely to erupt again |
| hotspring | forms when groundwater heated by magma rises to the surface and collects in a pool |
| geyser | a fountain of water and steam that erupts from the ground |
| geothermal energy | heat energy in earth's interior from water or steam that has been heated by magma |
