Theory Of Plate Tectonics

Question 1

Discuss your understanding of the theory of plate tectonics

Intro

Answer 1

• Plate tectonics is the theory of how the earth is split up into huge sections of land called plates and how convection currents moves these plates around in the mantle and the processes that occur because of this
• 3 types of plate boundaries convergent(constructive), divergent(destructive) and passive
  Constructive plate boundaries occur when plates separate and new land forms
  Destructive plate boundaries is when plates move towards each other and collide cause rocks to break this causes fold mountains and earthquakes
  Passive plate boundaries is when plates slide past each other causing huge friction which causes earthquakes

Question 2

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Answer 2

• At convergent plate boundaries plates collide, this is where most destructive earthquakes occur
• Plates collide which creates a lot of built up energy, this energy is stored in the rocks and eventually released as seismic waves

-An example is in March 2011 there was a shallow focus eq caused by Eurasian and pacific plate colliding
The pacific plate subducted underneath the Eurasian plate just 70km off the coast of Japan

• This caused catastrophic damage to Japan and the official death and missing persons toll surpassed 20,000 people
• The focus was only 2km below the earths surface

Question 3

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Answer 3

• At divergent plate boundaries plates separate and pull apart and continuously form new land
• It can cause continental separation in some cases like in Eastern Africa
• The African plate is separating from the Eurasian plate, this causes tears in the crust and this allows the continent to pull apart.
• Another process that occurs at divergent plate boundaries is sea floor spreading, plates at the sea floor spread apart allowing magma to flow up through the crust and cool and solidify when it hits the water
• This allows the formation of new land as the layers build up over millions of years to form the Mid-Atlantic ridge E.g of a country made in this way is Iceland