Download Types of Volcanoes

Crater Lake: Oregon
Mount Mazama Volcano
http://volcano-pictures.info/
Mauna Loa Hawaii fissure
What is a volcano: A weakened place in
the Earths crust where
magma erupts as lava.
Magma: Molten rock, gases, and water.
Melting from: Heat, pressure, and water
Lava: mostly molten rock, the gases and
water evaporate at the surface.
Major volcanic zones:
1. Ring of fire because of
subduction zones.
Island arcs
2. Mid-Ocean Ridges: seafloor spreading,
pillow lava’s
Iceland
Hot Spot Volcano’s: Hawaii, Yellowstone,
Congo,
1. Mantle plumes of magma feed these
volcano’s from deep in the mantle.
dike
Volcanic neck
Extinct volcano
Lava rock
sill
Plutons
Devils Tower is a Pluton
Section 2: Volcanic Eruptions
1. Mafic Eruptions: Magnesium Ma and iron Fe so….. MaFic
a. Low Silica (sand or quartz) and gas
b. Low Viscosity: Very runny lava
c. Quiet eruptions
d. Pahoehoe lava “ropy”: very mafic, runny
e. Aa lava: sharp jagged lava.
f. Blocky lava: higher
silica and viscosity.
Felsic Eruptions:
1. Violent
2. High in silica
3. Granitic in
nature.
Pyroclastic flow
Types of Volcanoes:
1. Shield volcano: like a shield laying upside
down.
Hawaii is a huge shield volcano
Hawaii shield
Composite Volcano alternating
layers of lava and ash build the
Volcano into its classic shape.
Ash layers
Lava flows
Toba Caldera: Indonesia
The eruption
takes place at
several places
at the same time
within the
volcano.
Cinder cone: Steep side and made of cinders.
Erupting cinder cone in Hawaii