Enormous slabs of lithosphere move unevenly over the planet’s spherical surface, resulting in earthquakes. This chapter deals with two types of geological activity that occur because of plate tectonics: mountain building and earthquakes. First, we will consider what can happen to rocks when they are exposed to stress. Stress is the force applied to an object. In geosciences, stress is the force per unit area that is placed on a rock. Four types of stresses act on materials.
