Volcanoes Some Key Terms. Plate Tectonics Separating ASH CRATER LAVA SIDE VENT CRUST MAGMA CHAMBER

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