Seismic hazard

Why do earthquakes occur? Earthquakes are a natural result of living on a dynamic planet. The greater part of the Earth’s interior is made up of the semi-molten mantle, which slowly turns over in vast convection currents caused by interior heating. The thin, mostly rigid crust of the planet on which we live is carried about on these currents, and the resulting stresses cause rocks to break along lines of weakness known as faults. Rocks bend, break and snap back releasing large amounts of energy in the form of waves that spread outward from the fault break. Each breaking event is what we call an earthquake.