Revision year 1 - Plate tectonics: earthquakes and volcanos

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Revision year 1 -
Plate tectonics: earthquakes and volcanos

Layers of the earth

Inner core: solid made out of nickel and iron. Very warm (4000 and 6000 degrees C.)

Outer core: liquid also made out of nickel and iron. Cooler around 3000 - 4500 degrees C.

 

Layers of the earth

Mantle: thickest layer of the earth, liquid but also moveable. 

Crust: layer we live on, solid and very thin. Made of rocks.

 

Earth’s crust is always changing

Natural forces

Exogenic                          Endogenic

change the Earth’s crust                         change the Earth's crust

from the outside                       from the inside

weatering / erosion                             vulcanos/earthquakes

Two different earth plates

1. Oceanic plate (Thin but heavy)
2. continental plate (Thick but lighter)

We have two types of tectonic plates:

Oceanic plates:

• Found under oceans, 
• thin (up to 10 kilometres)     but heavier. 
• Made of basalt.

Continental plates:

• Found under continents, 
• thick (up to 75 kilometres)     but lighter. 
• Made of granite.

Basalt

Granite

The puzzle pieces of the crust

The crust is broken up into several pieces called tectonic plates.

These plates move around because of convection currents (= movement of liquid rock in the mantle, caused by heat of the inner core).

Plate tectonics = The movement of tectonic plates.

Plate boundaries = The places where two plates meet.

So if you thought Earth plates were formed in the

following way, as in the video Ice Age, then you are

wrong. 

Plate tectonics is nothing new.

   

The earth's history is filled with plate movements, 250 million years ago all the plates formed one huge supercontinent called Pangea.

This process also happens in the mantle of the Earth.

Convection current causes fractures and thus the creation of earth plates.

Three different plate movements

1. Plates move away from each other = divergent movement
2. Plates move toward each other = convergent movement
3. Plates slide alongside each other = transform movement

Hypocentre and epicentre

Epicentre: Central point of the earthquake on the Earth’s surface.

Hypocentre: Location in the Earth where the stress has been released.

Richter Scale

Volcanism

Mid-oceanic ridge

Divergent plate movement in the ocean.

Mid oceanic ridge

• Divergent movement
  
• Oceanic and oceanic plate
  

Volcanoes in the oceans can become volcanic islands 

young maintain range vs old mountain range

Old mountain range

Young mountain range