What theory explains the motion of Earth's lithospheric pieces?

The theory that explains the motion of Earth's lithospheric pieces is plate tectonics. This comprehensive theory describes how the Earth's lithosphere, which is divided into several large and small tectonic plates, moves and interacts on the semi-fluid asthenosphere beneath it. Plate tectonics accounts for various geological phenomena, such as earthquakes, volcanic activity, and the formation of mountain ranges, as these plates continually shift due to convection currents generated by heat from the Earth's interior.

Plate tectonics unifies earlier concepts, such as continental drift, which focused primarily on the movement of continents, and explains it through a more robust framework that includes oceanic plates and their dynamics. By incorporating mechanisms like subduction, seafloor spreading, and transform boundaries, plate tectonics offers a holistic view of the complex processes that shape our planet over geological time. This integrated approach highlights the importance of relative plate movements in shaping the Earth's surface and helps to predict geological events.