| A | B |
|---|
| volcano | an opening in Earth's crust through which lava may flow |
| island arc | a string of volcanic islands made from melted rock rising up from beneath the sea floor |
| eruption | an outpouring of melted rock, ash, gases, or a combination of these |
| lava | hot melted rock that reaches earth's surface |
| vent | an opening of a volcano |
| crater | a cup shaped depression that forms around a vent of a volcano |
| caldera | a hole that forms when a volcano collapses within itself |
| dike | A _____________ forms when magma hardens between vertical or nearly vertical cracks |
| sill | A ____________ forms when magma hardens between horizontal layers of rock |
| laccolith | A dome shape formed when magma pushes upward and does not fill horizontal cracks |
| batholith | the largest and deepest of all underground magma formations |
| active volcano | a volcano that is erupting |
| dormant volcano | a volcano that has not erupted for some time |
| extinict volcano | a volcano that stops erupting |
| shield volcanoes | Built by thinner, fluid lava that spreads over a large area. These mountains have a broad base and gently sloping sides |
| Cinder-cone volcanoes | Cone shaped mountains built by thick lava that is thrown hight into the air and falls as chunks of cinder |
| composite volcanoes | A mountain formed by alternating eruptions of lava and ash |
| island chain | a line of volcanic mountains |
| hot spot | a stationary pool of magma |
| Ring of Fire | a circle of volcanoes which surrounds the Pacific Ocean |
