Why the Ground Shakes

The ground beneath our feet feels solid and unmoving, yet the surface of the Earth is actually broken into huge pieces called tectonic plates. These plates float on a layer of hot, soft rock and drift very slowly, only a few centimetres each year — about as fast as your fingernails grow. Where two plates meet, they sometimes push against each other. Instead of sliding smoothly, they can lock together while pressure keeps building for years. Eventually the rock can no longer hold, and the plates suddenly slip. This violent release of energy is what we feel as an earthquake. The shaking spreads outward in waves, which can crack roads, damage buildings, and, in serious cases, cost lives. The point deep underground where the movement begins is called the focus, while the spot on the surface directly above it is known as the epicentre. Although scientists cannot yet predict exactly when an earthquake will strike, they can identify the areas most at risk. With stronger buildings and better warnings, people living in these regions can stay much safer.