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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