Plates are a massive, irregularly shaped slabs of solid rock, generally composed of both continental and oceanic lithosphere. Earthquakes occur when convection currents in the mantle causes plates to move. When the plates converge/diverge/slide past each other, their movement is not smooth. This causes stress to build up in the rocks, and when the stress is suddenly released when the rocks snap or are displaced along a fault, there will be tremors or vibrations in the Earth's crust (an earthquake). These earthquakes can occur both on land and in the ocean. …
