Volcano  Vocabulary
 

1. 2 definitions of volcano-
    
   1. An opening in the surface of the Earth that allows lava, gas,
      and pyroclastic material to reach the surface.
   2. The mountain built by repeated eruptions of a volcano.
       
2. Paricutin-
   A volcano in Mexico. This volcano was produced in a farmers field in 1943 and built a 1300 foot cinder cone over 9 years. The volcano was name for the village that was destroyed by a large lava flow from its namesake.
    
3. Active Volcano-
   A volcano that is currently erupting or has erupted in recorded time.
    
4. Dormant Volcano-
   A volcano that is not erupting currently but has erupted in recorded time and is considered likely to do so again.
    
5. Extinct Volcano-
   A volcano that has not erupted in recorded time and is not considered likely to do so.
    
6. Lava Dome-
   A lava dome is a steep mass of very thick and pasty lava that is pushed up from the main vent.
    
7. Viscosity-
   The thickness of lava and magma determine how the volcano will erupt, what type of lava flow will be formed, and what type of volcanic cone will form. Viscosity is the measure of how thick or thin the lava is. Thick magma or lava is said to have a high viscosity, while thin lava or magma is said to have low viscosity.
   
    
8. 3 ways that volcanoes form
    
   1. Subduction Zone Volcanoes-Form where two plate meet, one being driven down into the mantle. These are the most explosive volcanoes because as the plate is driven into the mantle ocean water is mixed into the magma causing the production of steam which makes the magma more explosive.
   2. Rift Zone Volcanoes-These are formed where two plates are separating, magma fills the void left by the divergent plates. These volcanic mountains form a chain that circles the Earth. It is the longest continuous mountain chain in the world, over 40,000 miles long.
   3. Hot Spot Volcanoes-They form where there is a upward flow of very hot solid rock coming from great depths in the mantle. The Hawaiian Islands and Yellowstone Caldera were formed from a volcanic hot spot as the plates moved over that particular hot spot.
       
9. Tilt Meter-
   Tool that measures the amount of change in the slope of a volcano or a lava dome. It is used to help predict an upcoming eruption. The movement of magma in a volcano is a sign that an eruption may be near.
    
10. Magma-
    Molten rock under the surface of the Earth.
     
11. Magma Chamber-
    A large mass of magma usually located far under the surface of the Earth.
     
12. Fissure-
    A long crack in the surface of the Earth that allows magma and gases to reach the surface.
     
13. Dike-
    An intrusion of magma that becomes a passageway for magma. This passageway connects the conduit to the side vent. A dike runs through already existing layers of rock.
     
14. Side Vent-
    A secondary opening in a volcano that allows magma to reach the surface of the Earth. It is usually located on the flanks of a volcanic cone.
    
     
15. Lava-
    Molten rock that has reached the surface of the Earth.
     
16. Conduit-
    The main passage for magma.
     
17. Main Vent-
    The main opening in a volcano. Located at the top of the conduit.
     
18. Crater-
    The steep walled bowl shaped opening surrounding the main vent. This steep walled structure is formed by repeated eruptions of ash and lava.
     
19. Tuff-
    The rock that is formed by the mixture of lava and ash. This is the rock that is formed on the sides of stratovolcanoes.