VOLCANOES By Nora Printy

Volcanoes are one of the most dynamic, powerful, and visible forces on Earth.

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VOLCANO

A landform that forms from lava and tephra

TEPHRA

Tephra

Rock fragments ejected by a volcanic eruption

The Roman god, Vulcan

VULCAN

Volcanoes are based off of the Roman god of fire, Vulcan

VISCOSITY

Viscosity
  • Liquids'(or semi-liquids') consistency
  • Liquids with a high viscosity are very thick, and move slowly(ex:honey)
  • Liquids with a low viscosity are very flowy and move fast(ex:water)
The inside of a volcano

ERUPTION STYLES

Different eruption styles result in different types of volcanoes

Eruption styles

TYPES OF VOLCANOES

Cinder Cone
Composite Volcno
Shield Volcano
Lava Dome

VOLCANO FORMATION

Hot spot

HOT SPOTS

  • Form far away from plate boundaries
  • Are in both continental and oceanic plates

There are between fifty and 100 hot spots in the world

Spreading center

SPREADING CENTERS

  • Where tectonic plates are diverging
  • Plates spread apart and a path for the magma to come to the surface of Earth is created
  • Can extend into continental plates(ex:The Great Rift Valley in East Africa)
  • The magma is mafic
  • Some of the magma erupts, but most of it cools under Earth's surface
  • Commonly found along fault zones
Subduction

SUBDUCTION

  • Two tectonic plates converge
  • The denser one is pushed underneath the other one
  • Volcano forms at the leading edge of the top plate
  • The descending plate s heated and forms magma
  • Magma rises to the surface and a belt of composite volcanoes are formed
  • Felsic and intermediate magma is formed
  • Usually no volcanoes are formed when two continental plates collide

When a continental and oceanic plate collide, the oceanic plate goes under the continental plate

Magma

MAGMA

  • Melted(molten) rock inside of Earth
  • Composed of elements, minerals, and gases that were present in the rock before it melted
  • Major elements--Oxygen(O), Silicon(Si), aluminum(Al), iron(Fe), calcium(Ca), sodium(Na), magnesium(Mg), and potassium(K)
  • Also containsdissolved gases ex:water vapor
Mafic magma

MAFIC MAGMA

  • High melting point
  • low viscosity
  • High density
  • Forms shield volcanoes and cinder cones

Also forms flood basalts and fissure eruptions

Flood basalt

Flood Basalts

The outcome of (a) huge volcanic eruption(s) on large amounts of land or ocean floor that has basalt in it

Fissure eruptions

Fissure Eruptions

A linear volcanic vent where lava erupts, but there is usually no explosive activity

Intermediate magma

INTERMEDIATE MAGMA

  • Intermediate melting point
  • Intermediate viscosity
  • Intermediate density
  • Forms composite volcanoes and lava domes
Felsic magma

FELSIC MAGMA

  • Low melting point
  • High viscosity
  • Low density
  • Form composite volcanoes and lava domes

Also makes calderas

Caldera

CALDERA

A huge volcanic crater usually formed by one huge eruption, making the mouth of the volcano collapse

KÄ«auea

A volcano in the Hawaiian islands(currently active)

Credits:

Created with images by skeeze - "volcano lava flowing"

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