When a shift occurs in the Earth's crust, the energy released radiates in the form of seismic waves. These seismic waves propagate through the Earth's layers and can be detected by instruments called seismometers. The energy carried by these waves can cause the ground to shake, and in some cases, cause significant damage to structures and infrastructure. The magnitude and impact of an earthquake depend on factors such as the amount of energy released, the location of the epicentre, and the local geology.