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Chapter 3 - 1  Volcanoes and Plate Tectonics
Right side
   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.
        2.  Ex. Hawaii, Yellowstone National Park
        3.  Fig. 3. Pg. 81
Chapter 3 - 2  Volcanic Activity
   magma chamber-
   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

Ch. 3 – 3 Types of Volcanoes
   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.