Planet Flashcards
When did the earth form?
4.5 billion years ago
Crust
- thinnest and least dense
Continental crust
-Thicker (30-50km) less dense and made of granite.
Oceanic crust
Thinner(7km) denser and made of granite
What is the lithosphere?
Crust + rigid upper mantle
Mantle
- 2900 km thick and denser than the crust.
- upper mantle is rigid, lower mantle is semi molten and the zone of convection currents
Outer core
2200 km thick made of molten iron and nickel; it is denser than the mantle
Inner core
1260 km thick, made of solid iron and nickel, 6000C, due to immense pressure it is tye densest layer of the earth
Constructive plate
Diverging away from each other
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I I
/ \
/. \
Destructive plates
Oceanic plate and continental plate are converging. Oceanic plate subducts under the continental plate
Collision
Two continental crusts converge towards each other, as they are the sale density, subduction does not occur,so they buckle and make fold mountains
Conservative
Two plates move along each other in opposite directions or the same direction, friction can cause one plate to sick and the pressure builds up and then jolts to release a powerful earthquake
What is richter scale?
Asseses the amount of energy and the intensity of the shaking. Evry point of the scale goes up 30_fold. It us measued on a seismograph
What is the mercalli scale’
Measures the impact of the earthquake by looking at structural damage,
What is a strato volcano?
- acidic lava
- ash clouds, pyroclastic flows
- narrow base, steep sides
- destructive largins
