Chapter 13 Study Notes
Volcanoes
1
• A _______ cone is rarely more than a few
hundred meters high, with slope angles up
to 40°, and formed from ______ eruptions.
– cinder
– explosive
2
• A large circular depression that forms
when the magma chamber below a
volcano partially empties, causing the
ground above it to sink, is called a ______.
– caldera.
3
• A _______ forms on the ocean floor in a
_________ zone.
– trench
– subduction
4
• An area of volcanic activity ____ from a
tectonic plate boundary is called a
________.
– far
– hot spot.
5
• Any activity that includes the movement of
______ to Earth’s surface is called
________.
– magma
– volcanism
6
• ________ volcanoes are also known as
_________.
– Composite
– stratovolcanoes
7
• _______ eruptions are produced by ____,
sticky lava with high viscosity and a high
volume of trapped gases.
– Explosive
– thick,
8
• ______ is cut by a fissure breaking it into
two parts.
– Iceland
9
• If the temperature of rock rises ______ the
melting point of the minerals the rock is
composed of the rock will ____.
– above
– melt.
10
• _____ plutons that can cover an area as
large as 100 km2 are called ________.
– Large
– batholiths.
11
• ____ is magma that flows onto Earth’s
_____.
– Lava
– surface.
12
• ____ is liquid rock produced _____ Earth’s
surface.
– Magma
– under
13
• Magma that is rich in _____ and silica is
called ______.
– feldspar
– felsic
14
• Magma that is rich in ______ and iron is
called ___.
– magnesium
– mafic.
15
• _____ lava forms on a _________ ridge.
– Pillow
– mid-ocean
16
• _______ are igneous rock formations
created when magma ____ __ reach
Earth’s surface, but cools and solidifies
____ the crust.
– Pluton
– does
– not
– inside
17
• Pyroclastic material ___ than 0.25 mm in
diameter is called volcanic ______.
– less
– dust
18
• _____ eruptions are produced by _____
lava with low viscosity and few trapped
gases.
– Quiet
– runny
19
• The eruption of Mount _________ was an
________ eruption.
– St. Helens
– explosive
20
• The Pacific ____ __ ____ is both a
major earthquake zone and volcano zone.
– Ring
– of
– Fire
21
• Three type’s volcanoes are _______,
_____, and ______ cone.
– composite
– shield
– cinder
22
• Volcanic ___, ____, blocks, _____, and
lapilli are all _______ materials.
– ash
– dust
– bombs
– pyroclastic.
23
• Volcanic _____ may be signaled by a
change in ______ activity.
– eruptions
– earthquake
24
• When an ______ volcano erupts, the
magma cools quickly, forming _____ lava.
– underwater
– pillow
25
• When lava cools rapidly, a crust forms on
the surface of the flow. If the flow
continues, the crust _______ and forms
volcanic rock known as ________.
– wrinkles
– pahoehoe.
26
• When oceanic lithosphere _____ beneath
oceanic lithosphere, an island ____ forms.
– subducts
– arc
The End!!!