science unit 9 flash cards
volcano
a mountain that forms from the earths crust when magma reaches the earths surface
magma
molten material beneath the earth’s surface
lava
molten material that has reached the earths surface
ring of fire
a major belt of volcano’s that stretches all around the pacific ocean
island arc
a series of volcanic islands created by converging plate boundaries
hot spot
an area where material from deep within the earths mantle rises through the crust and melts to form magma
magma chamber
an area beneath the volcano where magma collects
crater
a bowl shaped area that may form at the top of a volcano around the central vent
silica
a material found in magma that forms from the elements of oxygen and silicon
quiet eruptions
Happen if a volcano’s magma is hot or low in silica.
The gases do not bubble as violently.
The lava also flows out of the volcano easier
explosive eruptions
Happen if a volcano’s magma is high in silica.
The gases bubble much more violently.
The lava is very sticky and tends to get caught in the pipe of
the volcano.
cinder cone volcano
A steep cone shaped hill or mountain formed
by magma with a high silica content and
explosive eruptions.
composite volcano
Tall cone shaped mountains in which layers
of lava alternate with layers of ash.
shield volcano
A wide gently sloping mountain,
formed by thin layers of lava
hardening on previous layers.
caldera
a hole left when a volcano collapses
