Chapter 7 Vocabulary - Earth Science CK12

Active Volcano

currently erupting or showing sins of unrest

Dormant Volcano

are considered active volcanoes because they have erupted since the last ice age but currently not erupting

Effusive Eruption

a type of volcanic eruption in which lava steadily flows out of a volcano onto the ground

Eruption

a volcano becomes active and ejects lava, ash, and gases

Explosive Eruption

where cooler more viscous magmas, like andesite reach the surface

Extinct Volcano

volcanoes that are not expected to erupt in the future

Lahar

a destructive mudflow on the slopes of a volcano

Magma Chamber

a large pool of liquid rock beneath the surface of the Earth

Pyroclastic Flow

a dense, destructive mass of very hot ash, lave fragments, and gases eject explosively from a volcano, typically flowing downslope at great speed

Tephra

rock fragments and particles ejected by a volcanic eruption

Viscosity

the ability of a liquid to resist flowing.

higher silica (felsic) = higher ... they tend to stay below the surface or erupt explosively.

lower silica (mafic) = lower ... they are fluid and runny, they normally reach the surface

Caldera

a large volcanic crater, especially one formed by a major eruption leading to the collapse of the mouth of the volcano

Cinder Cone

a cone formed around a volcanic vent by fragments of lava thrown out during eruptions

Composite Volcano

large volcanoes (thousands of feet) generally composed of lava flows, pyroclastic deposits and mudflow (lahar) deposits, and lava domes, they are active for a long time (100,000 years) and erupt periodically

Shield Volcano

a broad domed volcano with gently sloping sides characteristic of the eruption of fluid basaltic lava

Supervolcano

an unusually large volcano having the potential to produce an eruption with major effects on the global climate and ecosystem

Geyser

a hot spring in which water intermittently boils sending a tall column of water and steam into the air

Hot Spring

a spring of naturally hot water, typically heated by subterranean volcanic activity

Lava Dome

a mound of viscous lava which has been extruded from volcanic event

Lava Plateau

landforms created by volcanic activity

A'a Lava

forms a thick and brittle crust that is torn into rough and jagged pieces, it can spread over large areas as the lava continues to flow underneath the crust's surface, it is more viscous (thicker and rough)

Pāhoehoe Lava

forms lava tubes where fluid lava flows through the outer cooled rock crust, it is less viscous, the surface is smooth and ropy

Pillow Lava

mafic lava that erupts underwater, it cools very quickly and forms spherical rocks, it is common at mid-ocean ridges