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Crater Lake: OregonMount Mazama Volcano

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 waterLava: 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’sIceland

Hot Spot Volcano’s: Hawaii, Yellowstone, Congo, 1.Mantle plumes of magma feed these volcano’s from deep in the mantle.

sill

dike

Volcanic neck Extinct volcano

Lava rock

Plutons

Devils Tower is a Pluton

Section 2: Volcanic Eruptions1.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.Violent2. High in silica3.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.

Lava flowsAsh layers

Toba Caldera: Indonesia

The eruption takes place atseveral placesat the same timewithin the volcano.

Cinder cone: Steep side and made of cinders.

Erupting cinder cone in Hawaii