Earthquakes

Earthquakes happen when there's a sudden release of energy from Earth's outer shell, causing the surface to shake. They're measured on the Richter scale, which basically records what level the tremor was: enough to shake a few tiles off a roof, or sufficient enough to destroy the building altogether.

Earthquakes are a lot harder to monitor than volcanic eruptions, but some techniques are used such as laser beams to detect plate movement, or a seismometer to pick up the vibrations in Earth's crust.

Claudio Núñez/Wikimedia

Now, scientists at the University of Pennsylvania believe they have found a new insight into why earthquakes happen, helping them to predict where they might occur.

Their results were published in Physical Review Letters