VOLCANOESVOLCANOESERUPTING MOUNTAINSERUPTING MOUNTAINS

VOLCANOESVOLCANOES What is a volcano?What is a volcano? A volcano is a A volcano is a

mountain caused mountain caused by erupting lava by erupting lava from the mantle.from the mantle.

VOLCANO FEATURESVOLCANO FEATURES What are the What are the

features of a features of a volcano?volcano?

VentVent: pathway the : pathway the magma takes from magma takes from the chamber to the the chamber to the cratercrater

Magma chamberMagma chamber: : the storage of the storage of magmamagma

CraterCrater: the bowl : the bowl shape at the top of shape at the top of a volcano.a volcano.

VOLCANO FEATURESVOLCANO FEATURES What are the What are the

features of a features of a volcano?volcano?

BombBomb: football : football shaped blob that shaped blob that cools in the aircools in the air

Pyroclastic flowPyroclastic flow: : Hot ash and gases Hot ash and gases that flow down the that flow down the mountain at great mountain at great speeds.speeds.

CinderCinder: a lava rock: a lava rock

VOLCANO FEATURESVOLCANO FEATURES What are the What are the

features of a features of a volcano?volcano?

LaharLahar: a mudflow : a mudflow caused by the caused by the eruption of a eruption of a volcanovolcanoLava flowLava flow: Lava : Lava flowing from a flowing from a fissure in the crust.fissure in the crust.

What is viscosityWhat is viscosity What is viscosityWhat is viscosity Viscosity is the ability Viscosity is the ability

of lava to resist flowof lava to resist flow High viscosity=slow High viscosity=slow

flow. Lava has lots of flow. Lava has lots of silica or lower temp.silica or lower temp.

Low viscosity=fast Low viscosity=fast flow. Lava has high flow. Lava has high temp or low silicatemp or low silica

High Viscosity FluidHigh Viscosity Fluid

Volcano locationVolcano location Where are most Where are most

volcanoes found?volcanoes found?

What are hot What are hot spots?spots?

They are found on They are found on plate boundaries.plate boundaries.

Hot spots are places Hot spots are places where magma is close where magma is close to the crust causing a to the crust causing a volcano, but not on a volcano, but not on a plate boundary. plate boundary.

Exp: Hawaii, Exp: Hawaii, Yellowstone, IcelandYellowstone, Iceland

Stop and Think!Stop and Think! Would a volcanic eruption be Would a volcanic eruption be

likely to occur on the east coast likely to occur on the east coast of the United States? of the United States?

Explain.Explain.

Different Types Of Different Types Of VolcanoesVolcanoes

What are the What are the different types of different types of volcanoes?volcanoes?

Cinder ConeCinder Cone

Composite cone/ Composite cone/ Strato volcanoStrato volcano

Shield coneShield cone

CalderaCaldera

Cinder conesCinder cones What are cinder What are cinder

cones?cones? Explosive volcanoes Explosive volcanoes

with very viscous with very viscous lava.lava.

Made out of cinder Made out of cinder rocks and very rocks and very steepsteep

Exp: Sunset crater Exp: Sunset crater in Az.in Az.

Cinder Cone VolcanoesCinder Cone Volcanoes

Shield conesShield cones What is a shield What is a shield

cone?cone? A broad and flat A broad and flat

volcano in the shape volcano in the shape of a shield.of a shield.

Made out of lava Made out of lava flows-lava is not flows-lava is not viscousviscous

Example: Hawaiian Example: Hawaiian IslandsIslands

Shield VolcanoesShield Volcanoes

Composite Cones/Strato Composite Cones/Strato VolcanoVolcano

What is a What is a composite cone?composite cone?

A composite cone A composite cone is a volcano made is a volcano made of everything. of everything.

Lava flows, lahars, Lava flows, lahars, cinders, pyroclastic cinders, pyroclastic flows etc.flows etc.

Most common typeMost common type Exp. Mt. St. Helens, Exp. Mt. St. Helens,

Vesuvius, KrakatoaVesuvius, Krakatoa

Composite VolcanoComposite Volcano

What is a caldera?What is a caldera? What is a caldera?What is a caldera? A huge crater left in A huge crater left in

the ground after a the ground after a volcano has erupted.volcano has erupted.

Calderas blow all the Calderas blow all the material out and material out and then collapsethen collapse

Exp: Yellowstone Exp: Yellowstone National ParkNational Park

Stop and Think! Stop and Think!

Stop and Think!Stop and Think! In 1883, the island of In 1883, the island of

Krakatoa was destroyed Krakatoa was destroyed by a tremendous by a tremendous volcanic eruption. Huge volcanic eruption. Huge amounts of volcanic dust amounts of volcanic dust were hurled into the air. were hurled into the air. This dust remained in This dust remained in the air for several years the air for several years before settling. These before settling. These years were referred to as years were referred to as the “years without the “years without summers.” Explain why summers.” Explain why this was so.this was so.

CalderaCaldera