Earth Flashcards
What are the layers of the Earth?
Crust, Mantle, Outer Core, Inner Core
Crust -
- Thin outer layer
- Made of solid rock and broken into plates
- Layer that we mine for resources
- 5-70km
- Oceanic and Continental crust
- Less than 1% of the entire Earth’s Mass
- -5 to 1000 degrees Celsius
Mantle -
- 2900km
- Lithosphere (Upper, Dense rock)
- Athenosphere (Lower, Plastic like fluid, hotter because its closer to the core.
- Convection currents
- 67% of the Earth’s Mass
- Around 3700 Celsius( different temps throughout the mantle)
- Made up of hot, dense, rock
- Flows very slowly
Outer Core -
- Liquid
- Made of Iron and nickel
- not under enough pressure to become solid,
- very high temperatures.
- Moves/flows
- 2200km
- ~5000 Celsius
Inner Core -
- Solid
- Iron and nickel
~1250km
~7000 degrees Celsius - Solid because of the pressure from the others layers around it
- Melting point increases with high pressure
What is the temperature of each layer?
Crust= -5 to 1000 degrees Celsius
Mantle= about 3700 celsius (but the temp. varies)
Outer Core= about 5000 celcius (temp varies)
Inner Core= about 7000 (temp. varies)
What is the depth of each layer?
Crust= 5 - 70km
Mantle= About 2900km (densest layer)
Outer Core= 2200km
Inner Core= 1250km
What are the different types of crust?
Oceanic and Continental
Oceanic crust (characteristics)
thin and dense
Why is the oceanic crust more dense than the continental crust?
-it is more compact due to the weight of the ocean above it smooshing it down overtime
Continental crust (characteristics)
thick and not as dense as the oceanic crust
What happen when the crusts meet?
- a subduction zone forms
- the oceanic crust slips underneath the contenetal crust
- this also causes an earthquake, and then a tsunami
- when the oceanic crust falls, it goes into a hotter area (therefore melting it)
- this magma must go somewhere so it goes back up to the surface forming new crust
How did the layers of the earth form
The earth was once a ball of hot lava. As the earth began to cool layers formed due to the
differences in density of what the lava is made up of. The more dense material sank to the
bottom and the less dense material stayed at the top or rose to the top.
Why is there convection in the Mantle?
- different temps throughout the mantle
- hotter portion of the substance rises and colder parts sink to the bottom
how do earthquakes happen?
- Tectonic plates moving
- most earthquakes happen on fault-lines (LA is right on top of one)
- Tectonic plates are always moving, earthquakes just happen when they suddenly slip because of the pressure build-up
Why do the tectonic plates move?
- due to the convection currents in the mantle, it pushes on the tectonic plates
- it either pushes them together (folding), or pulls them apart (forming ridges), or causes them to transform (creating earthquakes)
What is the Focus?
- the spot inside the earth where the tectonic plates moved and cause the earthquake
What is the Epicenter?
The epicenter is the spot above the focus
- it is right where the earthquake happened and is where the earthquake is strongest
What are faults?
- where one tectonic plate ends and one begins
How do we measure the strength of an earthquake and how does it work?
- Richter Scale
- It’s a scale from 1-10
- everytime it goes up by 0.1 it is 10 times stronger than before
- ex. a 7.2 earthquake is 100 times stronger than a 7.0 earthquake
What is mountain building?
- mountain building is when two crusts converge together
- there is nowhere for the crust to go except for up
What is folding?
- Folding is when two crusts converge together and form a “bump” in the earth
What is faulting?
- When there is movement along a fault line (where two tectonic plates meet)
What is volcanic activity?
- When lava comes up from the mantle to the surface
