Earthquake mechanics involve the study of how stress builds up in the Earth's crust due to tectonic plate movements. When the stress exceeds the strength of rocks, it causes a sudden release of energy, resulting in seismic waves that we feel as an earthquake. This process is primarily driven by the interactions of the Earth's tectonic plates. The point where the earthquake originates is called the focus, while the point directly above it on the surface is known as the epicenter. Seismographs are used to measure the intensity and duration of these seismic waves, helping scientists understand the earthquake's magnitude and potential impact on surrounding areas.