How Do Earthquakes And Volcanoes Work?

The Inner Core, Outer Core, Mantle, Asthenosphere, and Lithosphere, or, as more colloquially known, the five layers of the Earth. Although each layer is important, each living thing resides on the Lithosphere, which happens to rest on the Asthenosphere, the upper part of the Mantle. Forces caused by these two layers both contribute to the theory of Plate Tectonics, which happens to be interconnected to Earthquakes and Volcanoes.
Without Plate Tectonics, the other two occurrences simply cannot exist, Of course, to comprehend how Earthquakes and Volcanoes work, Plate Tectonics must be understood first. So, to digress, it is the theories of Seafloor Spreading, proposed by Harry Hess, and Continental Drift, conceived by Alfred Wegener united under