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1 Notes #2 Types of volcanoes Know there are two kinds of volcanoes: one kind with violent eruptions producing steep slopes and the other kind with voluminous lava flows producing gentle slopes. 1. The viscosity of magma determines what type of volcano forms and how hazardous it will be. Viscosity is the resistance of a liquid to flowing. What are some examples of viscous liquids? 1. The viscosity of magma determines what type of volcano forms and how hazardous it will be. Less viscous magma erupts from volcanoes and flows easily More viscous magma does not flow easily and traps gas When gas reaches the surface it can expand and explode 2. Shield volcanoes are formed from basaltic/low viscosity lava flows. Creates large volcanoes with low slopes 2. Shield volcanoes are formed from basaltic/low viscosity lava flows. 2. Shield volcanoes are formed from basaltic/low viscosity lava flows. •Are made from layers of lava flows •Are made from mafic magma that is rich in iron and magnesium •Are found at hot spots and on divergent plate boundaries where the mantle is melting

Notes #2 Types of volcanoes€¦ · Notes #2 Types of volcanoes Know there are two kinds of volcanoes: one kind with violent eruptions producing steep slopes and the other kind with

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Page 1: Notes #2 Types of volcanoes€¦ · Notes #2 Types of volcanoes Know there are two kinds of volcanoes: one kind with violent eruptions producing steep slopes and the other kind with

1

Notes #2 Types of volcanoes

Know there are two kinds of

volcanoes: one kind with violent

eruptions producing steep slopes and

the other kind with voluminous lava

flows producing gentle slopes.

1. The viscosity of magma determines

what type of volcano forms and how

hazardous it will be.

• Viscosity is the

resistance of a liquid

to flowing.

• What are some

examples of viscous

liquids?

1. The viscosity of magma determines

what type of volcano forms and how

hazardous it will be.

• Less viscous magma erupts from volcanoes and flows easily

• More viscous magma does not flow easily and traps gas

• When gas reaches the surface it can expand and explode

2. Shield volcanoes are formed from basaltic/low

viscosity lava flows.

• Creates large volcanoes with low slopes

2. Shield volcanoes are formed from basaltic/low

viscosity lava flows.

2. Shield volcanoes are formed from basaltic/low viscosity lava flows.

•Are made from layers of lava flows

•Are made from mafic magma that is rich in iron and magnesium

•Are found at hot spots and on divergent plate boundaries where the mantle is melting

Page 2: Notes #2 Types of volcanoes€¦ · Notes #2 Types of volcanoes Know there are two kinds of volcanoes: one kind with violent eruptions producing steep slopes and the other kind with

2

3. Cinder cones are small volcanoes made

from magma that is viscous enough to trap

some gas.•Have steep sides•Are made from mafic lava that shoots out of the vent creating a pile of pyroclastic material (pieces of rock)

Mt Lassen

4. Composite or stratovolcanoes are large volcanoes that

have violent, hazardous eruptions because they are made

by viscous magma.

•Have

moderately

steep sides

4. Composite or stratovolcanoes are large volcanoes

that have violent, hazardous eruptions because they

are made by viscous magma.

• Are made of layers

of felsic lava flows

and pyroclastic material

• Occur as a result

of subduction

• Are most explosive

when gas is trapped in the

magma

Mt Lassen

4. Composite or stratovolcanoes are large volcanoes

that have violent, hazardous eruptions because they

are made by viscous magma.

Before

During

After

Page 3: Notes #2 Types of volcanoes€¦ · Notes #2 Types of volcanoes Know there are two kinds of volcanoes: one kind with violent eruptions producing steep slopes and the other kind with

3

Pyroclastic

material: ash and

rocks are thrown

into the air

Pyroclastic flow: an avalanche of rock, ash and gas

Lahar: a mudflow (pyroclastic materials mixed

with water)

Lahar: a mudflow (pyroclastic materials mixed

with water)

Fumarole

A crack in

the crust

that emits

gases

Page 4: Notes #2 Types of volcanoes€¦ · Notes #2 Types of volcanoes Know there are two kinds of volcanoes: one kind with violent eruptions producing steep slopes and the other kind with

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Bubbling Mud Pots