| Definition |
Word |
| 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 |
| The pocket beneath a volcano where magma collects. | magma chamber |
| 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 hot, fast-moving type of lava that hardens to form smooth, ropelike coils. | pahoehoe |
| A slow-moving cooler type of lava that hardens to form rough chunks. | aa |
| The expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption. | pyroclastic flow |
| Said of a volcano that is erupting or has shown signs of erupting in the near future. | active |
| Said of a volcano that does not show signs of erupting in the near future. | dormant |
| Said of a volcano that is unlikely to erupt again. | extinct |
| A pool formed by groundwater that has risen to the surface after being heated by a nearby body of magma. | hot spring |
| A fountain of water and steam that builds up pressure underground and erupts at regular intervals. | geyser |
| Energy from water or steam that has been heated by magma. | geothermal energy |
| A wide, gently sloping mountain made of layers of lava and formed by quiet eruptions. | shield volcano |
| A steep, cone-shaped hill or mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening. | cinder cone volcano |
| 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 |
