The geographic feature created by the movement of **tectonic plates** is known as a **fault line**. Fault lines occur when stress builds up between tectonic plates, ultimately leading to abrupt shifts in the Earth's crust. These movements can cause seismic activity, including earthquakes. Fault lines are significant in geology because they reveal valuable information about the Earth’s interior and the dynamics of plate tectonics. Notable examples include the *San Andreas Fault* in California, which has been extensively studied due to its potential for large earthquakes and its impact on nearby communities.