What is the block of rock that forms the upper half of a fault called?

The block of rock that forms the upper half of a fault is known as the hanging wall. This terminology is derived from mining practices, where miners would position themselves below the rock face, hence, the rock above them was referred to as the hanging wall.

In a fault, when movement occurs, the hanging wall will move relative to the footwall, which is the block of rock that sits below the fault line. Understanding these terms is essential in geology, especially when analyzing fault movements, as they help describe and classify the motion of tectonic plates and the resulting geological formations. This knowledge is crucial for predicting geological hazards such as earthquakes, as well as for the exploration and extraction of natural resources from the Earth.