Volcano
Chapter 9
• 1) Refers to the
opening in earth’s
crust through
which molten
rock, gases and
ash erupt AND
• 2) the landform
that develops
around that
opening
Where???
• Where do
volcanoes occur?
• 1) At subduction
boundaries
• 2 at divergent
boundaries
• 3 – Over hot
spots
• Hot spot???
• Areas of volcanic
activity that
results from hot
material that rises
up in the mantle
• Hot spots don’t
move….the PLATE
does!
Types of Magma
• Viscosity
• Gas content
• Resistance to
flow (THICK!)
• More gas =
more
EXPLOSIVE
Lava Flows
•
•
•
•
Pahoehoe
Aa
Pyroclastics
Pillow lava
• Smooth
• Jagged
• Solid
fragments
• underwater
Types of Volcanoes
• Shield
• Cinder Cone
• Composite
• Caldera
• Broad, gentle
slopes (Mauna Loa)
• Small….normally
around composites
• Very large and
steep (Mount
Shasta)
• An extinct volcano
that has filled with
water
Largest Volcano in our Solar
System!
• Oylmpus Mons
• Mars