VOLCANOES

AA - a type of lava flow with a rough, fragmented surface.

Active volcano - volcano currently erupting or has had recent activity.

Crater - bowl-shaped depression in summit of volcano, formed by ejection of rock.

VOCABULARY

Caldera - gigantic basin at summit of volcano, formed by magma removal during eruption.

AniakchakAniakchakAniakchakAniakchak

VOCABULARYDike - a pipe-like structure radiating out from the neck; feeds lava to the volcano.

Dormant volcano - volcano not presently erupting but is likely to do so in the future.

Mt. RainierMt. RainierMt. RainierMt. Rainier

Extinct volcano - a dead volcano.

Ascension Ascension IslandIsland

Ascension Ascension IslandIsland

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Hot Spot volcano - volcanoes related to persistent heat source in the mantle (Mantle Plume).

YellowstonYellowstonee

YellowstonYellowstonee

VOCABULARY

Lava - magma that has reached the surface.

Magma - molten rock under the surface.

Neck - a vertical remnant of a former volcanic vent, formed by hardened magma.

Devils Devils TowerTowerDevils Devils TowerTower

Nuee Ardente - a fast-moving, “glowing cloud” or better yet, glowing avalanche, of hot volcanic ash and gas; deadliest of all volcanic phenomena.

VOCABULARY

Pahoehoe - a type of lava with a smooth surface.

Pyroclastic Flow - “broken fire”; any heated mixture of ash and pumice “hugging” the flanks of a volcano.

Ring of Fire - region of mountain building, earthquakes and volcanoes which surround the Pacific Ocean.

Volcano - an opening in the Earth’s surface where magma, gases and ash are expelled.