Earthquakes are energy that is released in the tectonic plate boundaries. Tectonic plates are giant slabs of rock that move around! The crust (outermost layer of the Earth) is made up of these tectonic plates. These tectonic plates can get stuck. When they do this, lots of pressure builds up. Kind of like when you press two things onto each other. This pressure can build up over millions of year. When the pressure is finally released, the energy shakes the tectonic plates around it. The shaking comes from the plate boundary, all the way to the place directly above it and around it. This is what an earthquake is. Buildings can topple over because their foundations may not be strong for the shaking. Earthquakes can built up coastlines and bays to make them stronger! Thousands of earthquakes happen every day, but some of them are very soft.