A normal fault is a type of geological fault that occurs when the Earth's crust is pulled apart. In this process, one block of rock, known as the hanging wall, moves downward relative to another block, called the footwall. This movement typically happens in areas experiencing extensional forces, where tectonic plates are moving away from each other. Normal faults are commonly found in regions like rift valleys and mid-ocean ridges. They can lead to the formation of features such as basins and mountain ranges. Understanding normal faults is essential for studying earthquakes and the geological history of an area.