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25 Cards in this Set
- Front
- Back
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What is the lithosphere? |
The crust and upper mantle |
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What is the asthenosphere? |
The partially melted layer within mantle |
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How much do tectonic plates move annually?
How do they move? |
2 cm
By convection currents |
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Describe P-Waves: |
-Push/ Pull motion (compressional) -Moves fast -Travel through anything |
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Describe S-Waves: |
-Side to Side -Moves slow -Travel through solid only |
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Describe L-Waves: |
-Surface wave -Slowest wave -Travels like ripples |
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What are 3 causes of earthquakes? |
-Sticking faults -Volcanic eruption -Meteor impact |
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What is the relationship between waves and distance from epicentre? |
The distance between S and P waves increases further from epicentre |
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Describe felsic lava: |
-High sillica content -Thick consistency -Light colour -Slow moving |
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Describe mafic lava: |
-Low silica content -Thin/ runny consistency -Dark colour -Fast moving
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How is the composition of lava different from magma? |
Gasses escape, and surface material is added |
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Define tephra: |
fragments of lava, the name is determined by its size (ash, blocks, bombs) |
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Define ash: |
less than 2mm |
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Define blocks: |
more than 64mm, ejected solid |
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Define bombs: |
more than 64mm, ejected as lava then hardens |
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What lava forms do volcanos on rifts create? |
-Pillow lava -Basalt plateaus -Columnar jointing |
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What makes subduction volcanoes have more explosive eruptions? |
-Thick -Gassy -Tephra rich |
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Where do hot spot volcanoes occur? |
In the middle of lithospheric plates |
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What are the 3 types of volcanoes? (Include a feature for each) |
1) Shield- fluid lava (basalt)
2) Cinder Cone- made from lava fragments
3) Strato/Composite- lava and ash alternate |
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What are the names for general magma features that force its way into fractures and rock layers? |
Igneous intrusions or plutons |
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Define dike: |
Vertical sheets of rock that cut across |
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Define sill: |
Horizontal sheets of rock that intrude parallel |
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Define laccolith: |
Dome shaped igneous mass between rock layers (chubby sill) |
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Define batholith: |
Large mass of igneous rock (core of mountain ranges) |
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Define volcanic neck: |
The solidified magma filling vent of an extinct volcano (plug) |
