Why earthquakes occur?
In order to understand Terramoto’s idea we first need to go deep underground in order to understand what causes earthquakes in the first place. According to the theory of plate tectonics developed in the 1960’s the earth’s interior is made up of two layers, the outer lithosphere and the inner asthenosphere. The lithosphere essentially “floats” on the asthenosphere and is broken-up into ten major plates. These plates are in constant motion relative to each other with a typical velocity of a few centimeters per year. Although the velocity in which the entire plate is moving is relatively constant, the velocity in which material is moving along intersections of plates, also known as fault lines, is not constant and is believed to be changing due to irregularities in the material composing these parts of the earth asthenosphere. These irregularities are attributed to rocks, sometimes kilometers in size, which are buried in the ground and can be found at times up to 20 kilometers below the
