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