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Volcanoes.

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Presentation on theme: "Volcanoes."— Presentation transcript:

1 Volcanoes

2 Basic Volcano

3 Draw This Types Formations Volcanoes Tephra Eruptions Lava

4 Types of Volcanoes Cinder cones Composite volcanoes Shield volcanoes
Lava domes

5 Volcanic Formations Caldera:  a depression created after a volcano empties most of the contents of its magma chamber in an explosive eruption 

6 Volcanic Formations Crater: formed by the outward explosion of rocks and other materials from a volcano.

7 Volcanic Formations Lava plateau: a flat, wide surface (plateau) that is formed when lava comes out of the ground and spreads out very quickly

8 Volcanic Formations Hot spots: places within the mantle where rocks melt to generate magma.

9 Types of Eruptions Strombolian eruption: clots of molten lava burst from the vent; looks like fireworks Vulcanian eruption: expulsion of ash-laden gas; forms clouds of ash Vesuvian eruption: ash-laden gas flows out violently; forms thick ash-clouds Peléan eruption: glowing lava, together with ash and gas are blown out from the crater, vertically upwards and falling in again .

10 Types of Eruptions Hawaiian eruption: along a fracture with burning lava flowing from the fracture; also occurs in a central vent, in which case incandescent lava gushes out in the form of a fountain Phreatic eruption: does not involve the outpour of lava; occurs when cold ground or water comes into contact with hot molten matter; steam is forced upwards containing debris of surface rocks. No new magma is erupted. Plinian eruption: ejects huge amounts of thick lava, with gases and ash, miles into the air. The light nature of the lava is carried miles away by the wind action,

11 Types of Lava Pillow lava:  occur under water - are erupted at mid-ocean ridges

12 Types of Lava Pahoehoe: smooth, billowy, or ropy surface

13 Types of Lava A’a: rough, jagged surface

14 Types of Lava Block lava: has a surface of large angular blocks

15 Types of Ejecta (Tephra)
Pyroclastic flow: a mixture of hot steam, ash, rock and dust Ash: particles are <2 mm in diameter Lapilli: are fragments 2 mm to 64 mm in diameter Bombs or blocks: are >64 mm

16 Sources http://eschooltoday.com/volcanoes/types-of-volcanoes.html
famouswonders.com geologyclass.org oceanexplorer.noaa.gov facweb.bhc.edu volcanoes-in-aus.weebly.com


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