What Moves?

Subduction, Seafloor spreading, Asthenosphere

Some people think earthquakes and volcanoes erupt spontaneously while mountains appear randomly. However that isn’t the case- they are caused by plate tectonics. Plate tectonics are a scientific theory that pertains to the large-scale motions of the Earth’s lithosphere (the rigid outermost shell) and formed form extreme core pressure. The concept of plate tectonics developed during the early 20th century and is the study of the mass of the earth and how the masses correlate to one another. The plates pull and push causing continental drift, which affects the earth by causing earthquakes, volcanoes and mountains. There are seven major tectonic plates, and minor plates, that are composed of Oceanic Lithosphere the hard outer shell of the Earth’s crust. Through subduction the plates are carried to the uppermost mantle. Material is lost in order to balance the formation of a new crust along margins, by the sea floor spreading. This provides the Earth’s total surface to remain the same through out. Movements of the plates occur because of the Asthenosphere, which turns over hot rock for a total of ten centimeters a year; located under the lithosphere. Within the asthenosphere are convection cells in which slowly turns over hot rock. The cooled rock then turns sideways and moves parallel to the Earth’s surface before returning back into the subduction zones and reheating. When this happens it is called a divergent plate boundary. Tectonic plates are able to move because the Earth’s Lithosphere has a low density and a higher strength than the underlying Asthenosphere. The temperature gets intense to the point where magma convection currents cause heat to rise slightly near the Earth’s crust. Fault lines, small openings in the Earth’s crust, where large pieces of crust are moving in different directions. An earthquake occurs when two tectonic plates collide and is along the transformation boundary fault lines. How strong the earthquake is, or...
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