Transcript The World of Volcanoes

The World of Volcanoes
Mrs. Lozano
What is a volcano?
• A mountain formed by lava and ash
What is Lava?
• Lava is magma that reaches Earth’s
surface
• Okay...I know what lava is, but what
exactly is Magma?
• Magma is hot, soft rock from Earth’s
mantle.
What is ash?
• Ash is small pieces of hardened lava
• Savage Earth Animation
How do volcanoes form?
• Continental plates and oceanic plates
collide
• Subduction occurs
• Melted rock becomes magma that
forces its way up between the plates
• Savage Earth Animation #2
How do volcanoes form?
Continental Drift
• Continental Drift Animation
Where are these “Subduction Zones?”
• Many volcanoes are located at plate
boundaries around the Pacific plate.
• The Pacific plate is often called the
“Ring of Fire”
Do all volcanoes look the same?
• No, there are many different kinds of
volcanoes such as:
• Shield Volcanoes that can be found in
Hawaii
• Cinder Cone Volcanoes can be found in
Costa Rica
• Composite Volcanoes like Mt. Saint
Helen
• And Fissure Volcanoes found in
Nicaragua .
Do subduction zones create all volcanoes?
• No, volcanoes can also be formed by
Hot Spots.
• Hot Spots are volcanic areas on the
surface of the Earth that are created
by a rising plume of magma.
• http://www.classzone.com/books/ear
th_science/terc/content/investigation
s/es0810/es0810page03.cfm
Volcanic Hazards
• Volcanoes can create landslides that
bury land, homes and sometimes
people.
Volcanic Hazards
• Volcanoes can create Earthquakes that
may produce hazards which include
ground cracks, ground deformation,
and damage to manmade structures.
Volcanic Hazards
• Pyroclastic Surge that spews
extremely hot ash that races down the
mountain and swallows everything in
its path.
Volcanic Hazards
• Lava flows are the most famous yet
the least dangerous of hazards.
Volcanic Hazards
• There are two kinds of lava flows:
– Pahoehoe
– `A`A
I love Volcanoes!!!!!!
• Although volcanoes are beautiful and
wondrous things, they can be harmful
and cause many disasters. It is better
to love volcanoes from a far off
distance.