Answer: An earthquake is the shaking of the surface of the earth caused by volcanic activity or movement around geological faults.
Earthquakes can be of a high magnitude or low magnitude. (magnitude is the size of the earthquake or the frequency of the vibrations caused by the earthquake.)
Earthquakes shakes with stronger vibrations in soft sand or mud that's why structures built on soft sand or mud are often destroyed in an earthquake.
Earthquakes shakes with small vibrations on bedrock because of the rigidity of the bedrock.
