Volcanoes Shield Composite Cindercone There are three types of volcanoes Formed by layer after layer of lava Usually have low silica content and gases can escape easily Has quiet eruptions ID: 790375
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Slide1
8th grade Earth Science
Volcanoes
Slide2ShieldComposite
Cindercone
There are
three types of volcanoes:
Slide3Formed by layer after layer of lava.
Usually have low silica content, and gases can escape easily.
Has quiet eruptions.
Extremely broad and flat in shape.
Found in Hawaii.
SHIELD VOLCANOES
Slide4Shield volcanoes have gently sloping sides that can stretch for miles.These pictures are Mauna Loa, a volcano on the Big Island of Hawaii.
SHIELD VOLCANOES
Slide5A typical Hawaiian Eruption
Slide6Can sometimes be called Stratovolcanoes.
Formed by alternating layers of lava flow and cinders or ash.
Has a high silica content and gases are usually trapped.
Has explosive eruptions.
Mount St. Helens and Mount Rainier in Washington.
COMPOSITE VOLCANOES
Slide7Mt. Mayon,
Phillippines
(left)
Arenal, Costa Rica (below)
Mt. Rainier, Washington
(bottom, left)COMPOSITE VOLCANOES
Slide81980 2000
Mount St. Helens ( COMPOSITE)
Slide9Eruption of Mt. St. Helens
VIDEO
Slide10Virtual Tour of Mt. St. Helens
Harry Truman – the man who refused to leave “his” mountain.
Mt. St. Helens (COMPOSITE)
Slide11Formed by layers of cinders and ash, not a lot of lava erupts from these volcanoes.Very explosive when it erupts.
Has trapped gases.
The shape is nearly perfect on all sides…
almost like an orange road pylon.CINDERCONE VOLCANOES
Slide12CINDER CONE VOLCANOES
Slide13This eruptions that created Paricutin began in 1943 and continued to 1952. Most of the explosive activity was during the first year of the eruption when the cone grew to 1,100 feet (336 m). The cone continued to grow for another 8 years but added only another 200 feet.
Psricutin, Mexico (CINDERCONE)
Slide14In mythology, Etna was identified as the location of the forge of Volcan
, home of the
Cyclopses, and where the giant Enceladus laid (eruptions being his breath and earthquakes being his motion). Etna’s beauty, frequent eruptions, and long record of eruptions makes it one of the world’s best know volcanoes.
Mt. Etna, Italy (COMPOSITE)
Slide15City of Pompeii, Mt. Vesuvius(COMPOSITE)
Slide16Images of Pompeii
Slide17Both pictures are the remaining core of the volcanic neck of a once active volcano.
Located in Wyoming (left)
Ship Rock, San Juan County
New Mexico (below)
Devils Tower/Ship Rock
Slide18Mt. St. Helens has been periodically erupting for the 2 years. It is building its peak back up --- slowly but surely.
Latest Eruptions
Slide19Montserrat Volcano in the Caribbean. A large explosion and dome collapse occurred on March 3, 2004, causing a high eruption column and basal surge.
Latest Eruptions
Slide20Latest Eruptions
Etna Volcano in Sicily
Late October, 2002
Slide21Lava – molten rock that oozes out of volcanoes.TephraAsh – smallest sized tephra
Cinders
– small pieces of cooled lava up to the size of a basketball.
Bombs – any projectile bigger than a basketball.
Materials thrown out of a volcano
Slide22Volcanic ash can cover areas like a snow storm
ASH – the smallest size tephra
Slide23Lava Ash
Slide24Lava Cinders
Slide25Bombs – cinders usually come out in a pyroclastic flow
Slide26Lava Bombs
Slide27Aa – Thick, chunky and difficult flow
Pahoehoe
– Thin, watery, and easily flows
Types of lava
Slide28Lava Flows
Slide29Dante’s Peak Eruption…
video