Volcanic and Seismic Events Are Major Pieces of Evidence Towards Proving That Plate Tectonics Theory Is Valid (40 Marks)

1855 WordsNov 19, 20128 Pages
Volcanic and Seismic events are major pieces of evidence towards proving that plate tectonics theory is valid (40 marks) The theory of plate tectonics states that the Earth’s lithosphere (top layer of the Earth’s crust) is split up into rigid sections called plates that are moving relative to one another as they move on top of the underlying semi-molten mantle. These plates are either continental, The North American Plate, or oceanic, The Nazca Plate. Tectonic plates are powered by convection currents, which is the circular movement of magma within the mantle. These currents are powered by the core, which heats the magma, causing it to rise, cool and fall back down. This circular motion causes the plates, which float on the mantle, to…show more content…
Earthquakes can be created on any of the plate boundaries. Earthquakes occur when tension is released from inside the crust. Plates do not always move smoothly alongside each other and sometimes get stuck. When this happens pressure builds up. When this pressure is eventually released, an earthquake tends to occur. The point inside the crust where the pressure is released is called the focus. The point on the Earth's surface above the focus is called the epicentre. Earthquake energy is released in seismic waves. These waves spread out from the focus. The waves are felt most strongly at the epicentre, becoming less strong as they travel further away. The most severe damage caused by an earthquake will happen close to the epicentre. But there are some anomalies as there are earthquakes which don’t take place on a plate boundary and it’s the same with volcanoes. An example of this is Hawaii. Hawaii is a volcanic island which is found in the middle of a tectonic plate. Hawaii is an example of a hotspot. The places known as hotspots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the mantle elsewhere. They may be on, near to, or far from tectonic plate boundaries. There are two hypotheses to explain them. One suggests that they are due to hot mantle plumes that rise from the core-mantle boundary. The other hypothesis postulates that it is not high

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