The block of rock that sits above a fault plane is called the hanging wall.

The block of rock that sits above a fault plane is called the hanging wall.

• A. Footwall
• B. Dip-slip block
• C. Fault block
• D. Hanging wall

Answer: (D)

Rocks separated by a fault form two blocks, defined by their position relative to the fault plane: the block that sits above the plane is called the hanging wall, and the block below is the footwall. The hanging wall name comes from mining terminology, where the rock above the fault plane would “hang” over the plane if not supported. So the statement identifying the block above the fault plane as the hanging wall matches this convention. The other terms don’t specify this vertical relation: a dip-slip block isn’t a standard descriptor for position, and a fault block is a general term for either side of a fault.

Rocks separated by a fault form two blocks, defined by their position relative to the fault plane: the block that sits above the plane is called the hanging wall, and the block below is the footwall. The hanging wall name comes from mining terminology, where the rock above the fault plane would “hang” over the plane if not supported. So the statement identifying the block above the fault plane as the hanging wall matches this convention. The other terms don’t specify this vertical relation: a dip-slip block isn’t a standard descriptor for position, and a fault block is a general term for either side of a fault.