theory of plate tectonics

The theory of plate tectonics explains that Earth's outer shell, called the lithosphere, is divided into large, rigid pieces called tectonic plates. These plates float on the semi-fluid layer beneath, called the asthenosphere. Their movement, caused by convection currents in Earth's mantle, leads to interactions at their edges—such as crashing together, pulling apart, or sliding past each other. These interactions cause geological phenomena like earthquakes, volcanic eruptions, and the formation of mountain ranges. Overall, plate tectonics is the unifying framework that describes how Earth's surface is dynamic and constantly changing over geological time.