Volcanoes Some Key Terms
Plate Tectonics Separating ASH 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 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
Pyroclastic
Cinder 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 Flow
Flood 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
Stratovolcano
What kind of eruption produces a… Explosive Eruption Intermediate Eruption Quiet Eruption