Chapter 3 - 1 Volcanoes and Plate Tectonics
Right side
Vocabulary
volcano-
magma-
lava-
hot spot-
What’s this? (figure)
1. The eruption of a volcano is among the most dangerous and awe-inspiring
events on Earth!
2. Location of Volcanoes
A. Fig. 1, pg. 79
B. There are ~600 active volcanoes on land
C. Many more lie beneath the sea
D. Notice anything strange in where the
volcanoes are located
in fig. 1?
1. Ring of fire = plate boundaries
Ring of Fire figure
E. Most volcanoes occur along:
1. Diverging plate boundaries
a. Such as
mid-ocean ridge
b. Subduction
zones
2. There are exceptions!
3. Exceptions
A. Island Arcs
1. Forms from magma rising to
the surface after
a plate has
subducted
2. Ex. Japan, New Zealand, Indonesia,
Caribbean
Is. Philippines
Fig. 2, pg. 80
B. Hot spot
1. Magma melts through the crust
and as the
plate moves
over it a string of volcanic is.
form
2. Ex. Hawaii, Yellowstone National
Park
3. Fig. 3. Pg. 81
Chapter 3 - 2 Volcanic Activity
Vocabulary
magma chamber-
pipe-
vent-
active volcano-
dormant volcano-
1. Volcanic eruptions
A. Think of it as a soda bottle being opened after
it was shaken!
B. During volcanic eruptions
1. Gases dissolved in magma rush
out
2. Carrying the magma (lava)
with them
2. Inside the volcano
A. Pg 85
3. Types of Volcanic Eruptions
A. Quiet eruptions
1. Produces two types of lava
2. Fig. 7, pg. 87
a. Pahoehoe
(smooth flow)
b. Aa (rough)
B. Explosive eruptions
1. Magma is thick and sticky
= explosive
2. Trapped gases explode quickly
3. Fig. 8 a,b,c,d, pg. 88
Mt St. Helens figure
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Ch. 3 – 3 Types of Volcanoes
Vocabulary
crater-
caldera-
Lava Plateaus-
1. Shield Volcanoes
A. Composed of quiet lava flows
B. Gently sloped, dome shaped
C. pg. 95
2. Cinder cones
A. Consists of cinders and other rock particles
B. Steep-cone shaped hill or mtn.
C. explosive eruptions
D. pg. 95
3. Composite Volcano
A. Alternating layers or rock particles and lava
B. Tall cone-shaped mtn
C. Alternates between quiet and explosive eruptions
D. Pg. 95
4. Landforms from magma
A. Fig. 12, pg. 96 & fig. 13, pg. 97
B. Volcanic necks, dikes, sills, batholiths and
dome mtns.