Volcanic and Seismic Events Are Major Pieces of Evidence Towards Proving That Plate Tectonics in Valid Discuss the Extent to Which You Agree with This Statement.
If we map out the divisions between plates, it would show the distribution of volcanoes around the world. These plates are either continental, The North American Plate, or oceanic, The Nazca Plate. Convection currents power tectonic plates, 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 move. This was known as the plate tectonic theory. Convection currents in the mantle caused by radiation and heat from the earth’s core move the earth’s plates. The plates are constantly in relative motion to each other, but this motion is extremely slow due to the incredible amount of mass being moved, friction, and the high density of the asthenosphere.
Volcanoes represent releases of energy from inside the earth’s crust and upper mantle. There are about 500 active volcanoes that are closely associated with plate boundaries. Magma rises at the plate margin to create the volcanic activity. During the course of the year only a small number (20-30) of the active volcanoes erupt. Their eruptive events are relatively short and are separated by periods of low activity. Earthquakes however are a series of vibrations and shock waves, which are initiated by volcanic eruptions or movements along the plate boundaries. They result from the build up and the release of pressure created by plate tectonic activity.
Wherever there is movement in the earth’s crust earthquakes will form. The build up of pressure in the earth’s crust will build up creating friction. Eventually this pressure will be released and the earth will shake creating an earthquake. Most earthquakes are caused by sudden movement along fault plains.
Earthquakes at constructive margins are shallow in focus (0-70km) caused by rising magma and tension in the crust. Most are submarine (except along the East African Rift valley) and pose little hazard usually lass that 4 on the Richter scale. This is due to the fact the plates are moving away from each other and little tension builds up. Earthquakes at destructive plate boundaries (oceanic-oceanic or oceanic-continental) tend to be intermediate focus (70-300) or deep focus (300-700km) and result in major events, for example the Japan Tsunami March 2011. They are more destructive due to subduction zones along the Benioff Zone. The Benioff Zone is a sloping plane where two plates ride over one another. The friction created will produce earthquakes, and heat which will destroy the two plates.
At the constructive boundaries the convection currents rise forcing the crust to crack. New Basaltic magma rises to the surface, cools and pushes the plates apart. The convection currents also help drag the plates apart and then pull them down at convergent