Imagine holding a cane. Put pressure on both the ends of the cane. After some time, the cane will blend and then break. This is the way a cane deals with the stress that you have put on it. Earth deals with stress in a similar way. The inner layers of the Earth are made of plates. When these plates stretch or squeeze, they put pressure on each other. When the pressure is large enough, the huge rocks in the Earth shift, and Earth’s crust breaks. This causes the Earth shift and Earth’s crust breaks. This causes the Earth to shake and an earthquake happens.