Earthquakes contribute to the geological processes of mountain building and plate tectonics by releasing built-up energy along fault lines, which can lead to the movement of tectonic plates. This movement can result in the uplifting of mountain ranges as plates collide or compress against each other. Additionally, earthquakes can trigger volcanic activity, which also plays a role in mountain building. In terms of plate tectonics, earthquakes are often associated with the boundaries between tectonic plates, where the most significant geological activity occurs.