Explain, with reference to examples that you have studied, how the theory of plate tectonics helps to explain the distribution of earthquakes around the world.
Plate tectonics has only being gathering serious momentum since the beginning of the 1900s as scientist began to learn more and more about the earths make up. They eventually discovered that the world is made up of seven major plates. Earthquakes generally happen where these plates meet or as commonly known as plate boundaries. These plates are in constant motion and this motion is coming from forces deep down inside the earth. At the very centre of the earth is the core and surrounding it is a very thick layer known as the mantle. On top of the mantle is a thin layer of rock k
nown as the crust and this is where we live. Huge convection currents force their way trough the mantle and all the way up to the crust. At the crust they separate and begin to spread out. It is this movement that then drags the crust in different directions that eventually causes earthquakes. Earthquakes commonly occur where two converging plates meet. An example of this is along the indian-pakistan border. This is where the indian plate is crashing into the eurasian plate. As the plates slowly press into each other huge pressure is built up over the years. Eventually this pressure releases its energy in the form of seismic waves and an earthquake occurs. These types of earthquakes can be very powerful. earthquakes are measured on a scale called the richter scale. it measures the strength using a scale fr
om 0-10 and each unit increase means a ten fold increase in power, 10 being the strongest. Other common areas of earthquakes are where two plates move side by side. These are known as passive plate. A very well known example is the san
Andreas fault line in california. Where plates separate, diverging plate boundaries, earthquakes also occur. These quakes tend to be weak and are rarely felt as they are out in the ocean. When large quakes do occur at sea tsunamis can result such as the st Stephen’s day quake that devastated muck of south asia in 2004. In the centre of plates there is a very little chance of an earthquake happening as the friction will not be able to build up to cause one. If a quake does happen in the centre of a plate boundary this is usually very slight and is as a result of an ancient plate boundary being close by.
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