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Volcanoes: What They are and How They Work
Presentation By Justin Ventline
Agenda How They are Formed What the are made of Where they are located Different types What triggers an eruption What happens during an eruption The Aftermath
How They are Formed
Magma makes it way through the upper mantle to the earths surface.
How They Are FormedOnce the
magma makes it to the surface it is called lava, and the lava collects around the earths opening forming a mountain type shape
What They are Made Of
Once the lava cools in a mountain shape a young volcano has formed.
Also, the ash and rock that is moved will help form the volcano
What They are Made OfLava Ash & Rock
Where they are located
Most volcanoes are found on the shores of oceans or seas where the earths plates are either colliding or separating
Where They are LocatedA very famous string of volcanoes is called the “Ring of Fire”The red dots or lines are once active or currently active volcanoesContains 452 volcanoes and over 75% of the worlds active volcanoes
The Ring
OfFire
Different Types
There are 4 Types of Volcanoes
Cinder Cones
CompositeShieldLava
Domes
Different TypesCinder = simplest
typesComposite =
steepest and tallestShield = slowly
slopping or flatDomes = very wide
but not very tall
Cinder
Composite
Shield
Domes
What Triggers an EruptionThere are three
theories of how a volcano erupts
1. Magma rises due to pressure of gas
2. Chemical changes in the gas and water
3. New magma is injected into the volcano
What Triggers an EruptionThere are also 3 types of eruptions1. Hawaiian
Non-destructive and lava flows out slowly
2. Strombolian Not dangerous but more impressive than
Hawaiian
3. Plinian Very Destructive, magma shoots 50km into
the air, has been known to destroy cities and can destroy everything in its path
What Happens During an Eruption
What Happens During an EruptionMagma is
forced from the chamber up to the opening turning into lava
In some cases if there is enough pressure the lava will explode into the air or just flow
Gas and ash leave the volcano via the air.
The AftermathTowns or villages in the area can be destroyed
The gas and ash in the air can block the sun for days, causing the temperature to lower for 1-3 years!!!
The volcano will grow in size due to the lava and rock hardening
References Clearly Ambiguous, Scott Robinson Oligarki, Richard Aprilandrandy, April and Randy Dom Dada, Dominik Wheeling Jesuit , Initials. (2004, November 24). Exploring the envrionment
of volcanoes. Retrieved from http://www.cotf.edu/ete/modules/volcanoes/vlocation.html
Olaf141, Gus MacLeod watson, JW. (1997). Principle types of volcanoes. Retrieved from
http://pubs.usgs.gov/gip/volc/types.html Pillai, MP. (2010). Volcanic eruptions: what makes volcanoes erupt.
Retrieved from http://www.buzzle.com/articles/volcanic-eruptions-what-causes-volcanoes-to-erupt.html
www.yourdictionary.com/ahd/v/v0139800.html http://www.orbitforkids.com/doubletakes/purple/dt_p_awesomeforces.html