For example, the Himalayas were created when the Indian plate crashed into the Eurasian plate. In the collision oceanic sedimentary deposits were pushed vertically to great altitudes. This explains why you can find marine fossils in mountain environments. Earthquakes are also a result of plate tectonics. They occur at faults, tectonic plate boundaries, and at the mid-oceanic ridge.
Most earthquakes result after the sudden movement of one mass rock relative to another mass.
The rock resisted movement in the past because of friction. However, pressure and stress builds up until the friction is overcome. The size of an earthquake is relative to potential energy build up before the friction is overcome. When the energy is released wave energy is created. These seismic waves then travel through the ground creating earthquake movement and shaking.