| A | B |
|---|
| aa | jagged chunks of lava formed by rapid cooling on the surface of a lava flow |
| caldera | large basin-shaped depression formed when an explosion destroys the upper part of a volcanic cone or when the magma chamber below a volcano is emptied during an eruption |
| cinder cone | steep-sloped deposit of solid fragments ejected from a volcano |
| composite volcano | also called stratovolcano, steep-sloped volcanic deposit with alternating layers of hardened lava flows and pryorclasitc materials |
| crater | funnel-shaped pit at the top of a volcanic cone |
| felsic lava | silica-rich lava |
| fissure | crack in a rock surface through with lava flows |
| hot spot | area of volcanism within a lithospheric plate |
| lapilli | pyroclastic particles between 2 mm and 64 mm in diameter |
| lava | magma that reaches the earth's surface |
| mafic lava | dark-colored lava rich in magnesium and iron |
| magma | liquid rock produced deep inside the earth |
| pahoehoe | solidified mafic lava with a wrinkled surface |
| pillow lava | lava that flows out of fissures on the ocean floor and cools rapidly in rounded shapes |
| pyroclastic material | the rock fragments ejected from a volcano |
| shield volcano | has a cone of hardened lava that forms a broad base and gentle slopes |
| stratovolcano | also called composite volcano, steep-sloped volcanic deposit with alternating layers of hardened lava flows and pryorclasitc materials |
| vent | opening through which molten rock flows onto the earth's surface |
| volcanic ash | pyroclastic particles between 0.25 mm and 2mm in diameter |
| volcanic block | the largest possible pyroclastic material that is formed from solid rock blasted from a volcanic fissure |
| volcanic bomb | large, spindle shaped clot of lava thrown out of a volcano |
| volcanic dust | pyroclastic particles less than 0.25 mm in diameter |
| volcanism | any activity that includes the movement of magma toward or onto the earth's surface |
| volcano | lava and pyroclastic material built up on the earth's surface around a vent |
| Factors that allow magma to push its way upward include temperature and | color |
| Activity caused by the movement of magma is called | extraterrestrial |
| The belt of volcanoes that encircles the Pacific Ocean is called | the subduction zone |
| Island arcs are formed by the collision of | two plates with continental crust at their edges |
| Areas of volcanism within plates are called | hot spots |
| Lava that breaks into jagged chunks when it is subjected to rapid cooling is called | aa |
| Explosive volcanic eruptions result from | mafic lava |
| Pyroclastic materials that form into rounded or spindle shapes as they fly through the air are called | ash |
| The Hawaiian Islands are formed from | shield volcanoes |
| A cone formed only by solid fragments built up around a volcanic opening is a | shield volcanoe |
| The depression that results when a cone collapses into an empty magma chamber is a | crater |
| Shortly before a volcano erupts, magma may cause its surface to | bulge out |
| Scientists have discovered that before an eruption, earthquakes | completely stop |
| Olympus Mons, the largest known volcano in the solar system, is found on | the moon |
| The material ejected from volcanoes on lo is probably | sulfur and sulfur dioxide |
