Volcanoes form from tectonic plate movement or hot spots in the mantle. They allow gases and molten rock to exit the earth's surface. Mount St. Helens is located in Washington state and began forming 40,000 years ago. Its last eruption from 2004-2008 sent ash into the atmosphere and grew its lava dome. Environmental effects included ashfall and steam plumes seen on nearby mountains.

1. Volcanoes
Julie Jochem

2. What is it?
• A vent that allows gases, molten rock, and
debris to leave earth’s mantle
• Created by tectonic plates that are moving
away from each other

3. • A volcano can also be formed when one tectonic plate
hits another.
• When this happens, one plate goes underneath the other
and melts there due to the heat of the earth’s heat.
• In Hawaii, volcanoes are created by “hot spots” which
are places of extreme heat in the mantle, causing the
molten rock to bubble and move to the surface
– Scientists believe these volcanoes are formed by a mantle
plume; a column

4. Mount St. Helens
• Located in Washington state
• It began forming 40,000 year ago
• The last eruption took place in 2008
– The eruption began in 2004, lasting for 4 years
– The volcano is 8,365 feet high
– It has a diameter of 1,300 feet

5. Environmental effects
• Sent tons of ash and other gases into the atmosphere
• As a lasing effect, the lava dome at the top of the
volcano grew
• Ash and steam have been seen on the mountain and
other mountains in the area
• There were very few, if any, displaced people during this
event because many people didn’t even realize it was
happening

6. Sources
• http://environment.nationalgeographic.com/environment/natural-disasters/volcano-profile/ -
Volcanoes
• http://library.thinkquest.org/03oct/00795/volcano.html - Volcanoes
• http://geography.about.com/od/hazardsanddisasters/a/mountsthelens.htm- Mount St Helens
• http://pubs.usgs.gov/fs/2000/fs036-00/ - Mount St Helens – From the 1980 Eruption to 2000
• http://volcanowatcher.wordpress.com/mount-st-helens/ - Mount St. Helens
• http://www.fs.usda.gov/mountsthelens - Explore Mount St Helens
• http://www.newworldencyclopedia.org/entry/Mount_Saint_Helens - Mount Saint Helens
• http://www.netamatixblog.com/ - image
• http://www.alaska-in-pictures.com/plume-of-ash-1082-pictures.htm - image

7. Sources
• http://environment.nationalgeographic.com/environment/natural-disasters/volcano-profile/ -
Volcanoes
• http://library.thinkquest.org/03oct/00795/volcano.html - Volcanoes
• http://geography.about.com/od/hazardsanddisasters/a/mountsthelens.htm- Mount St Helens
• http://pubs.usgs.gov/fs/2000/fs036-00/ - Mount St Helens – From the 1980 Eruption to 2000
• http://volcanowatcher.wordpress.com/mount-st-helens/ - Mount St. Helens
• http://www.fs.usda.gov/mountsthelens - Explore Mount St Helens
• http://www.newworldencyclopedia.org/entry/Mount_Saint_Helens - Mount Saint Helens
• http://www.netamatixblog.com/ - image
• http://www.alaska-in-pictures.com/plume-of-ash-1082-pictures.htm - image