Causes of earthquakes

An earthquake is a sudden movement of the Earth’s crust. They mainly occur along the edges of the Earth’s tectonic plates. These plates, vast segments of the Earth’s crust, are in constant motion. However, this movement is not always smooth. Earthquakes occur at destructive, conservative and constructive plate margins. At destructive (convergent) and conservative (transform) plate margins, where plates collide or slide past each other, friction often hinders their movement. This build-up of stress and friction can eventually lead to a dramatic release of energy, triggering an earthquake. Earthquakes are not limited to just these types of margins, though. They also occur at constructive (divergent) margins, where plates move apart, though they tend to be less powerful.

The point beneath the Earth’s surface where this release begins is called the focus, and the point directly above it on the surface is the epicentre.

The depth at which an earthquake occurs can significantly influence its magnitude; shallower earthquakes tend to be more powerful and cause more surface damage than those at greater depths. This is because energy from deep earthquakes dissipates more before reaching the surface, resulting in less intense ground-level shaking.