Earthquakes
Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through Earth’s rocks.
Seismic waves are produced when some form of energy stored in Earth’s crust is suddenly released, usually when masses of rock straining against one another suddenly fracture and “slip.”
Earthquakes occur most often along geologic faults, narrow zones where rock masses move in relation to one another.
The major fault lines of the world are located at the fringes of the huge tectonic plates that make up Earth’s crust.
The earth has four major layers: the inner core, outer core, mantle and crust. The crust and the top of the mantle make up a thin skin on the surface of our planet.
But this skins it not all in one piece it is made up of many pieces like a puzzle covering the surface of the earth. Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other.
We call these pieces tectonic plates, and the edges of the plates are called the plate boundaries. The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults. Since the edges of the plates are rough, they get stuck while the test of the plate keeps moving. Finally, when the plate has moved far enough, the edges unstick one one of the faults and there is an earthquake.
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