Plate tectonics is about the large-scale movement of the Earth’s surface. We know that the Earth is composed of layers of rocks and other materials. The outermost layer of the Earth, called the lithosphere, lies above another layer known as the asthenosphere (Louie). The asthenosphere is a layer composed of molten materials, so in form, it can be considered as a hot liquid, with the solid lithosphere floating on it. The lithosphere is divided into several parts called the tectonic plates. Since they are floating in the liquid asthenosphere, these plates tend to move, in relation to one another.
The movements of these tectonic plates are the main cause of mountain building, volcanic activity, and earthquakes. Activities caused by plate tectonics often occur in the plate boundaries. These are caused by the different types of movements between the plates. There are three different types of movement exhibited by these plates, and these movements also characterize the type of plate boundaries. These are divergent, convergent, and transform boundaries. The diverging plate boundaries are caused by the divergence or moving apart of two plates. This is known as the extensional movement.
The plates slide apart each other because a plume of hot magma surfaces, pushing the crust upward, which would then force the plates to separate. Divergent plates create rifts, and as they grow farther apart, they create rift valleys. This type of boundary would create massive fault zones, which could progress further into earthquake creating boundaries (Extreme Science). The next type is the convergent boundaries. This is characterized by the movement of the plates wherein they slide toward each other (Moorland School). This is known as the compressional movement.
This type of movement often leads to a creation of a subduction zone or a continental collision. We have two types of plates; the first one is composed of continental crust while the other one is composed of oceanic crust. When two plates converge, the outcome would depend on the type of plate involved. The last type is the transform boundary, characterized by sliding or grinding movement of plates between their boundaries. This is known as the transform movement. This movement between plates creates stress, as it builds up when rocks slide past each other.
When the strain threshold of these rocks is exceeded, it releases the accumulated potential energy as a strain, and this occurrence is felt by the people in the form of an earthquake. Transform movements aren’t the only ones that can cause earthquakes. The other plate movements an also cause earthquakes depending on the situation. At the diverging boundaries, the extensional movement creates shallow earthquakes aligned along the axis of the plates’ spread. At this situation, earthquakes tend to have magnitudes smaller than magnitude 8.
At the transform boundaries, the transform or the strike-slip movement of the plates create shallow earthquakes with magnitudes smaller that magnitude 8. 5. Finally, at the converging boundaries, the compressional movement of plates creates earthquakes varying in depth, from the very near surface to several hundred kilometers deep. This movement causes the largest earthquakes of the Earth, with recorded magnitudes exceeding magnitude 9 (Louie). Plate tectonics play an important part in the different activities occurring in Earth. It is responsible for the formation of mountains, volcanic activities, and the occurrence of earthquakes.
These can all be attributed to the movement of the plates in relation to each other, made possible by the hot, molten asthenosphere just below the outermost layer of the Earth. Works Cited: Extreme Science. “How Plate Tectonics Works”. 2008. May 28 2009. <http://www. extremescience. com/PlateTectonicsmap. htm>. Louie, J. “Plate Tectonics, the Cause of Earthquakes”. 2001. May 28 2009. <http://www. seismo. unr. edu/ftp/pub/louie/class/100/plate-tectonics. html>. Moorland School. “Tectonic Plates”. 2008. May 28 2009. <http://www. moorlandschool. co. uk/earth/tectonic. htm>.