VOLCANOESVOLCANOES

Pompeii, ItalyPompeii, Italy

Bodies…Bodies…

Pompeii, ItalyPompeii, Italy

Terms to know…Terms to know…►Magma-Magma- liquid rock liquid rock►Lava-Lava- magma that breaks through to magma that breaks through to

the surface of the earththe surface of the earth►Vent-Vent- opening through which magma opening through which magma

flowsflows►Volcano-Volcano- structure formed by the vent structure formed by the vent

and the volcanic material that builtsand the volcanic material that builts►Pyroclastic material- Pyroclastic material- ash and rock ash and rock

material ejected from a volcanomaterial ejected from a volcano

VolcanoesVolcanoes

Where do volcanoes happen?Where do volcanoes happen?►Subduction zones- Subduction zones- Pacific Ring of Pacific Ring of

FireFire►Mid-Ocean Ridges-Mid-Ocean Ridges- fissures (breaks fissures (breaks

and cracks, Iceland)and cracks, Iceland)►Hot Spots-Hot Spots- notnot along plate along plate

boundaries- areas of volcanic activity boundaries- areas of volcanic activity within the platewithin the plate

Where?Where?

What erupts?What erupts?►LavaLava

►Mafic- oceanic, slow Mafic- oceanic, slow ►Felsic- continents, fastFelsic- continents, fast

►GasesGases►Rock fragments or Pyroclastic MaterialRock fragments or Pyroclastic Material

►Volcanic AshVolcanic Ash►Volcanic DustVolcanic Dust►Volcanic Bombs (hot) and Blocks (cold)Volcanic Bombs (hot) and Blocks (cold)

3 Types of Volcanoes3 Types of Volcanoes► Shield VolcanoShield Volcano► Cinder ConeCinder Cone► Composite VolcanoComposite Volcano

Shield VolcanoShield Volcano► Broad baseBroad base►Gentle sloping sidesGentle sloping sides► Covers a wide areaCovers a wide area► Lava builds up Lava builds up

slowly to form slowly to form volcano bodyvolcano body

►Quiet eruptionsQuiet eruptions►Hawaiian IslandsHawaiian Islands

Cinder ConeCinder Cone► Explosive eruptionsExplosive eruptions► Very steep sides (40 Very steep sides (40

degrees or more)degrees or more)► Solid fragments Solid fragments

(pyroclastic material) (pyroclastic material) that are ejected that are ejected make the volcano make the volcano bodybody

► Rarely more than a Rarely more than a few hundred meters few hundred meters highhigh

Composite VolcanoComposite Volcano► Both explosive and Both explosive and

quiet eruptionsquiet eruptions► Body of volcano Body of volcano

made of alternating made of alternating layers oflayers of lava lava (quiet (quiet eruptions)eruptions) and and pyroclastic pyroclastic materialmaterial (explosive (explosive eruptions)eruptions)

►Mt. St. Helens (USA) Mt. St. Helens (USA) and Mt. Fuji (Japan)and Mt. Fuji (Japan)

The Ring of FireThe Ring of Fire►Ring Of Fire IMAX movieRing Of Fire IMAX movie►Other VideosOther Videos►Volcano Concept MapVolcano Concept Map►Plotting the Ring of FirePlotting the Ring of Fire