Volcanos – Book F Chapter 6

• Shield Volcano- broad, gently sloping volcano formed by quiet eruptions of basaltic lava.

• Composite Volcano-volcano built by alternating explosive and quiet eruptions that produce layers of tephra and lava; found mostly where Earth’s plates come together and one plate sinks below the other.

• Cinder Cone- steep –sided, loosely packed volcano formed when tephra falls to the ground.

Types of Volcanos Found on Earth

broad, gently sloping volcano formed by

quiet eruptions of basaltic lava.• Kilauea (Hawaii)

• Mauna Loa (Hawaii)

• Etna (Sicily)

• Piton de la Fournaise (Reunion)

• Erta Ale (Ethiopia)

• Fernandina and all Galapagos volcanoes

• Nyamuragira (Congo)

• Karthala (Indian Ocean)

• Savai’i (Samoa)

• Aoba (Vanuatu)

Shield Volcano

Volcano built by alternating explosive and quiet

eruptions that produce layers of tephra and

lava; found mostly where Earth’s plates come

together and one plate sinks below the other.

• Mount Fuji-Japan

• Mount Cotopaxi- Ecuador

• Mount Hood- Oregon

• Mount Rainier and Mount St.

Helens- Washington

Composite Volcano

steep –sided, loosely packed volcano

formed when tephra falls to the

ground.• California Cinder Cones

• Cerro Negro, Nicaragua

• Lava Butte, Oregon

• Newberry Caldera Vicinity, Oregon

• New Mexico Cinder Cones

• Paricutin, Mexico

• Portland Vicinity, Oregon

• Sunset Crater, Arizona

• Wizard Island, Crater Lake, Oregon

Cinder Cone

The reason volcanoes occur is

because when the Earth’s plates

pull apart they cause magma to

rise to the surface. Volcanoes

can also occur above hotspots

and where one plate goes

beneath another, forcing the

magma to rise above the

surface.

Why do volcanoes occur?

Volcanic eruptions occur in certain place

and don’t randomly occur. The reason for

this is because the Earth’s outermost

shell. (The lithosphere) is broken into a

series of slabs known as lithospheric or

tectonic plates. These plates are rigid,

but they float on the hotter, softer layer

in the Earth’s mantle.

Where do volcanoes usually occur?

The hot temperatures inside the

Earth’s mantle can melt rock;

creating magma.

• Magma can reach up to 700 and

1300 degrees Celsius depending

on the chemical composition of

the rocks.

• All igneous rock found on the

Earth was originally formed as

magma.

Magma

is the molten rock that comes out of

volcanoes during eruptions

• Lava can range in temperature from

about 750 degrees C to more than

1100 C.

• The temperature of the lava actually

depends on the composition of the

minerals in it. Some contain large

amounts of aluminum, potassium and

calcium, while others have iron and

magnesium.

Lava

• Magma is a liquid rock inside

a volcano

• Lava is a liquid rock (magma)

that flows out of a volcano.

What is the difference between lava and magma?

• Igneous rocks are formed from the molten

liquid minerals that lie below the earth’s

crust. They’re formed from magma that

cools beneath the earth’s surface or from

lava that cools upon the earth’s surface.

• Lava cools quickly and forms rocks with

small crystals. They are called extrusive

igneous rocks. Basalt is an example of this

type of rock. Obsidian is an example of

another extrusive igneous rock that cooled

so fast that it has no crystals and looks

like shiny, black glass.

Types of rocks formed when magma and lava cool and how.

• Extrusive (volcanic) - produced when magma

flows on the earth's surface

• Intrusive (plutonic) - produced when magma

solidifies at depth beneath the earth.

• Silica

• Obsidian

• Feldspar

• Quarts

• Amphiboles

• Pyroxenes

• Olivine

• Mica

• Basalt Granite

Types of Igneous Rock features formed from volcanic activity.

• Location- East Antarctica

• Summit - 3,794/ 12,447

• Hazards/Damage- Lava flows, some minor

explosions from Strombolian-style eruptions,

tephra/ash fall.

• Last known eruption- Start Date- December

1972 (on or before) Stop Date- 2011 (in or

after) January 14th, 2011 but is erupting as an

open vent system. Persistent current activity.

• The volcano always has hot gas and lava ,

creating surreal caves and towers. Has ice

caves and a pool of lava (one of the few of its

kind)

Mount Erebus