Why do earthquakes occur?
Earthquakes occur due to the rubbing of tectonic plates against each other.
Earth is made up of crust, mantle and core. Core, as the name suggests is the inner-most filling of earth. Mantle forms the layer above the core, which is also a place to deposit for magma rocks, molten lava, etc. that keep collecting from centuries. Earth’s surface, i.e., the part which we inhabit is known as the crust. The crust is held together by various tectonic plates scattered all around the world. These plates are just beneath the crust, which make it suitable for the land mass to rest on them.
Though it may not be vividly evident to us, but these plates are constantly moving at a steady pace. In the course of this movement, there comes a stage when two tectonic plates in any particular part of the world come within touching distance of each other. As these plates stay together for a while, friction occurs between them. Due to this naturally induced friction, the two plates begin to rub against each other.
However, mere rubbing of tectonic plates cannot be termed as an earthquake. Earthquake happens when this abrasion actually results in the breaking of tectonic rocks, thereby emitting a tremendous amount of energy in form of seismic vibrations. These vibrations diffuse rapidly along the radius of the energy produced, to result in tremors in various parts of land, or an earthquake, in a nutshell. The point where the rocks shatter to produce a vibration is known as the focus of the earthquake or the hypocenter. Whereas, the land surface just above the hypocenter is called as the epicenter.
While the clashing of tectonic plates against each other emerges as the chief reason in the context of earthquakes, there have also been instances where other natural and man-made causes have brought about an earthquake. Natural causes such as volcanic eruptions cause earthquakes by permeating right through the earth’s crust to the tectonic plates, which as a consequence, are set in motion to rub against each other. Man-made occasions such as underground nuclear testing, controlled blasts to build underground tunnels, mining accidents such as mine roofs caving in, or mine doors exploding have also played a part in bringing about earthquakes, albeit of little intensity.
Therefore, earthquakes are caused by a handful of reasons, but mainly due to the rubbing of tectonic plates.