What is an earthquake, and why do they happen?

What is an earthquake?
An earthquake is the sudden shaking of the ground caused by the sudden movement and breakage of large parts of the earths most outer crusty layer, which are known as tectonic plates. Most earthquakes occur when two or more plates slide past or collide with each other.

Why do earthquakes happen?

Earthquakes usually happen when rock from under the earth suddenly breaks along a fault ( a surface where two blocks of the earth slip past one another suddenly. ) The sudden release of energy leads to seismic waves that cause the ground to shake. When two plates rub against each other they don’t slide smoothly they catch on each other a little bit. These blocks are not moving but intact pushing against each other. Due to the pressure build up after a while the rocks break. When the breakage of rocks occurs, thats when the earthquake happens. Both afterward and during the earthquake the plates continue to move until they get stuck again. The place underground where the rock breaks is known as the hypo centre of the earthquake and the place which is above the focus, but on top of the ground is known as the epicentre of the earthquake.

How is an earthquake measured?

The strength of an earthquake is measured using the Richter magnitude scale. The Richter scale ranges from 1 to 10 and measures the amount of seismic energy released by an earthquake.