| A | B |
|---|
| a weak spot in the crust where magma has come to the surface | volcano |
| the molten mixture of rock-forming substances, gases, and water from the mantle | magma |
| liquid magma that reaches the surface | lava |
| a major belt of volcanoes that rims the Pacific Ocean | Ring of Fire |
| a string of islands formed by the volcanoes along a deep-ocean trench | island arc |
| an area where magma from deep within the mantle melts through the crust above it | hot spot |
| a substance that cannot be broken down into other substances | element |
| a substance in which two or more elements are chemically joined | compound |
| any characteristic of a substance that can be observed or measured without changing the composition of the substance | physical property |
| the resistance of a liquid to flowing | viscosity |
| a material found in magma that is formed from the elements oxygen and silicon | silica |
| a hot, fast-moving type of lava that hardens to form smooth, ropelike coils | pahoehoe |
| a slow-moving type of lava that hardens to form rough chunks | aa |
| the pocket beneath a volcano where magma collects | magma chamber |
| a long tube through which magma moves from the magma chamber to Earth's surface | pipe |
| the opening through which molten rock and gas leave a volcano | vent |
| the area covered by lava as it pours out of a volcano's vent | lava flow |
| a bowl-shaped area that forms around a volcano's central opening | crater |
| the expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption | pyroclastic flow |
| describes a volcano that is not currently active, but that may become active in the future | dormant |
| describes a volcano that is no longer active and is unlikely to erupt again | extinct |
| a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions | shield volcano |
| a steep, cone-shaped hill or small mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening | cinder cone |
| a tall, cone-shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials | composite volcano |
| the large hole at the top of a volcano formed when the roof of a volcano's magma chamber collapses | caldera |
| a deposit of hardened magma in a volcano's pipe | volcanic neck |
| a slab of volcanic rock formed when magma forces itself across rock layers | dike |
| a slab of volcanic rock formed when magma squeezes between layers of rock | sill |
| a mass of rock formed when a large body of magma cools inside the crust | batholith |
| the heating of underground water by magma | geothermal activity |
| a fountain of water and steam that builds up pressure underground and erupts at regular intervals | geyser |
