why and how does an earthquake occur

An earthquake occurs when there is a sudden release of energy from within the Earth's crust. This energy is generated by the movement of tectonic plates, which are large sections of the Earth's crust that slowly move and shift over time.

Tectonic plates move because of the heat generated by the Earth's core, which creates convection currents in the mantle. These currents cause the plates to move and interact with each other, sometimes colliding or sliding past one another.

When two tectonic plates come together, the boundary between them is called a fault. As the plates move against each other, they create friction, which builds up pressure along the fault. Eventually, the pressure becomes too great and the rock breaks, causing an earthquake.

The energy released by the earthquake is sent out in waves that travel through the Earth's crust and can be felt on the surface as shaking. The severity of the earthquake depends on the size of the fault, the amount of pressure built up, and the type of rock involved.

Earthquakes can also be triggered by other factors, such as volcanic activity, landslides, or human activity like drilling or mining. However, most earthquakes are the result of tectonic plate movement.