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.