What causes earthquakes to occur?

Earthquakes occur due to the movement of tectonic plates along faults in Earth’s crust. When plates grind against, collide with, or pull away from each other, stress builds up at the boundaries. This stress is released suddenly as seismic energy, causing the ground to shake. Earthquakes are common near plate boundaries, such as the Pacific Ring of Fire. The intensity of an earthquake depends on the amount of energy released and the depth at which it occurs.