Volcanoes - Vocabulary Flashcards

Vocabulary flashcards covering key volcano concepts from the notes.

hot spot

an area where material from deep in the mantle rises and melts, forming magma.

lava

molten rock found at Earth’s surface.

magma

molten rock found beneath Earth’s surface.

magma chamber

a large pool of magma deep under Earth’s surface.

pipe

the channel in a volcano through which magma rises to reach Earth’s surface.

vent

the opening at the top of a volcano.

plates

Earth’s crust is broken into major pieces called plates.

plate boundaries

where two plates meet; the three types are divergent, convergent, and transform.

divergent boundary

plates move away from each other; magma flows out of cracks in crust; forms rift valleys and mid-ocean ridges.

convergent boundary

subduction occurs; magma breaks through crust; volcanic mountains form on land; island arcs form at sea.

transform boundary

plates slide past one another at boundaries.

subduction

the process of one denser plate sliding under a lighter plate; crust material becomes molten rock; molten rock rises toward surface; volcanic activity occurs on the lighter plate.

volcano

a weak spot in Earth’s crust where molten material comes to the surface.

viscosity

the measure of a liquid’s resistance to flow.

quiet eruption

an eruption where magma is low in silica and has low viscosity; gases bubble out gently; lava flows quietly.

explosive eruption

an eruption where magma is high in silica and high in viscosity; gases trapped cause violent expulsion; lava breaks into fragments that cool and harden.

shield volcano

a landform formed by lava flows that build broad, gently sloping mountains.

cinder cone volcano

a landform formed from explosive eruptions of ash and cinders.

composite volcano

a volcano composed of alternating lava flows and volcanic ash layers; tall and steep.

lava plateau

a landform created by lava flows; not visible until surrounding rock erodes.

caldera

a large volcanic crater formed when the magma chamber empties after eruption.

volcanic neck

a pipe that fills with hardened magma.

batholith

a large mass cooled deep inside Earth.

dome mountain

raised crust from hardened magma.

dike

a vertical intrusion of magma that cuts through older rock layers.

sill

a horizontal intrusion of magma that cuts across rock layers.

geyser

a geothermal feature where heated water erupts.

hot springs

places where water is heated by magma.

mud pots

pools of boiling, acidic mud.

active

erupting or shows signs of erupting again soon.

dormant

hasn’t erupted for a long time but may erupt in the future.

extinct

unlikely to erupt again.

crater

a bowl-shaped depression around the vent of a volcano.

lava flow

the movement of lava down the sides of a volcano.