Earthquakes happen constantly all over the world when rocks underground move suddenly because of a build-up in surrounding pressure. This generally happens along a natural break in the rock, such as a fault or fracture zone produced by tectonic movement in the past. If the movement is large, a large amount of energy is released, and the ground shaking can cause a lot of damage. However, these sorts of events only tend to happen along tectonic plate boundaries, where the Earth’s crust is moving at incredibly fast rates. At the other end of the scale, tiny movements along small, natural faults and fractures such as those in Cornwall release much less energy and generally go unnoticed.