Download Volcanoes - Science

Volcanoes
Basic Volcano
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Types
Formations
Volcanoes
Tephra
Eruptions
Lava
Types of Volcanoes
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Cinder cones
Composite volcanoes
Shield volcanoes
Lava domes
Volcanic Formations
• Caldera: a depression created after a
volcano empties most of the contents of
its magma chamber in an explosive
eruption
Volcanic Formations
• Crater: formed by the outward explosion
of rocks and other materials from a volcano.
Volcanic Formations
• Lava plateau: a flat, wide surface (plateau)
that is formed when lava comes out of the
ground and spreads out very quickly
Volcanic Formations
• Hot spots: places within the mantle where
rocks melt to generate magma.
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
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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,
Types of Lava
• Pillow lava: occur under water - are erupted
at mid-ocean ridges
Types of Lava
• Pahoehoe: smooth, billowy, or ropy surface
Types of Lava
• A’a: rough, jagged surface
Types of Lava
• Block lava: has a surface of large angular
blocks
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
Sources
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http://eschooltoday.com/volcanoes/types-of-volcanoes.html
http://volcanology.geol.ucsb.edu/frags.htm
http://education.nationalgeographic.org/encyclopedia/caldera/
famouswonders.com
geologyclass.org
oceanexplorer.noaa.gov
http://volcano.oregonstate.edu/
facweb.bhc.edu
volcanoes-in-aus.weebly.com
www.geo.cornell.edu