VolcanoesVolcanoes

Some Key TermsSome Key Terms

Plate Tectonics SeparatingASH

CRATER

LAVA

SIDE VENT

CRUST

MAGMA CHAMBER

Types of Eruption

• Quiet Eruption

• Explosive Eruption

• Fissure Flows

• Intermediate Eruption

Quiet Eruption

• Low pressure, lava pours out in steady stream and thinly, calm – often called Hawaiian – produces a shield cone - wide base, and

gentle, convex slope– gases emitted slowly

Shield ConeShield Cone

Explosive Eruption

• Great violence, often earthquakes or loud rumblings preceding the eruption

• Volcanic bombs (pyroclastics)

• Produces a cinder cone - narrow base, steep side

• Volcanoes not very high because material is loosely organized– e.g.Krakatoa 1883

PyroclasticPyroclastic

Cinder ConeCinder Cone

Fissure Flows

• An open crack in solid surface produces a lava plateau or plain many kilometres wide– looks like a ribbon of magma/fire

• Produces a flood basalt "cone" or lava plateau

Fissure Flows

• When it erodes it "candles" like fresh water ice in hexagonal columns!!!– Ireland - Giant's

Causeway

Fissure FlowFissure Flow

Fissure FlowFissure Flow

Flood BasaltFlood Basalt

Intermediate Eruption

• Also called Strombolian - a combination of quiet and explosive eruptions

• A combination of lava and rock fragments in alternating layers (produces pyroclastics during explosive phase)

• Produces a composite cone or stratovolcano

StratovolcanoStratovolcano

What kind of eruption produces a…

Explosive EruptionExplosive Eruption

Intermediate EruptionIntermediate Eruption

Quiet EruptionQuiet Eruption