Volcano

 

 

 

3 states

Opening that erupts gases, ash, & lava

 

Over 600 active volcanoes

 

active, dormant-sleeping, extinct-dead!

Kilauea

 

 

Land of Fire & Ice

Hawaiian volcano, world’s most active, has been erupting for 25 years

 

Iceland, has glaciers and volcanoes, is part of Mid-Ocean Ridge

Magma

 

 

 

Lava

Rock melted by heat & pressure deep inside Earth

 

Less dense than mantle-“floats” to surface

 

Magma that reaches the surface

Vent

 

Crater

 

 

Opening in Earth, mouth of a volcano, lava comes out

 

Steep bowl-shaped area around a vent

 

 

Volcano

Mountains formed of layers of lava, ash, and rocks from the vent

 

Dangerous-lava flows, ash clouds, exploding rocks, poisonous gases

Lava flows

 

Pyroclastic flow

Lava runs downhill, can be slow

 

Ash, rocks, and other matter (not lava), rushing down side of volcano-very dangerous!

Volcanoes

Mostly form at divergent and convergent boundaries

Divergent forms a fissure or trench volcano

 

Convergent forms at subduction zone-more explosive!

 

Hot spots

NOT near plate boundaries-weak spot in crust where magma is near surface.

 

Hawaiian Islands, Yellowstone National Park

3 types of volcanoes

Shield, not tall-formed only from lava-Hawaiian volcanoes

 

Cinder cone-formed from pyroclastic explosions, very steep

 

Composite volcano-formed from layers of lava and pyroclastic explosions.