Study Guide (Part 4)
Volcanoes
Key Vocabulary Terms for Part 4:

Caldera – a large crater-shaped basin

Cinder cone – the simplest type of volcano, forms when molten lava is thrown into the air
from a vent

Composite Volcano – when layers of materials from successive explosive eruptions
accumulate around a vent

Hot Spot – areas of volcanic activity that result from plumes of hot solid material that have
risen from Earth’s mantle

Lahar – a fast-moving mudflow that occurs when the heat from a volcanic eruption melts
snow and ice on top of a volcano

Lava Plateau – a plateau formed from basaltic lava pouring from a crack in Earth’s surface

Pyroclastic Flow – a dense, superheated cloud of gases and pyroclastic materials that moves
rapidly downhill from an erupting volcano

Shield Volcano – a shield-shaped volcano with a broad base and gently sloping sides that is
made of basaltic lava

Volcano – an opening in Earth’s crust that molten rock, gases, and ash erupt through; also
the landform that develops around the opening
Notes for Part 4:

What plate boundaries are volcanoes likely to form at (pg. 194)? Divergent boundaries and
subduction boundaries

Where do volcanoes form at subduction boundaries (pg. 195)? On the overriding plate
Study Guide (Part 4)

Why do they form this way at subduction boundaries (pg. 195)? The plate that is
subducting under the other plate melts and the newly formed magma then rises to the
surface of the overriding plate because it is less dense then the surrounding material.

Where does most of Earth’s volcanic activity take place (pg. 196)? Underwater

Mid-ocean ridges are associated with what type of plate boundary (pg. 196)? Divergent
boundaries

What are the causes of volcanoes that are not near plate boundaries (pg. 197)? Hot spots

Do hot spots move? What does (pg. 197)? No the lithospheric plates move across them
creating volcanic island chains

What type of lava is associated with shield volcanoes and why (pg. 202)? Basaltic lava
because of its low viscosity flows easier and allows for it to create a larger base to
support a large volcano.

Compare and contrast a composite volcano from a shield volcano (pg. 202-203). Shield
volcanoes have broad, gently sloping sides and have less explosive eruptions. While
composite volcanoes are steeper and made from materials thrown out from violent
eruptions.

What type of volcano forms in groups near other larger volcanos (pg. 202)? Cinder cones

List in order from largest to smallest the 3 main volcanoes (pg. 202-203):

o
Shield volcano
o
Composite volcano
o
Cinder cone
What can form from a composite volcano blowing its top (pg. 204)? A caldera
Study Guide (Part 4)
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

List in order the most explosive to least explosive type of volcano (pg. 202-203):
o
Composite
o
Cinder cone
o
Shield
What type of magma is associated with more explosive eruptions (pg. 199)?
o
Andesitic
o
Rhyolitic
What are 2 destructive effects from explosive volcanoes (pg. 201 & 203)?
o
Pyroclastic flow
o
Lahar

What kind of destruction can result from non-explosive volcanos (pg. 204)? Lava plateau

The most volcanically active area in the world is around the Pacific Ocean and is called the
“Ring of Fire”.
Study Guide (Part 4)
Study Guide (Part 4)
Study Guide (Part 4)