Hanging Wall Faults

When movement along a fault is the reverse of what you would expect with normal gravity we call them reverse faults.

Hanging wall faults.

This type of faulting is common in areas of compression when the dip angle is shallow a reverse fault is often described as a thrust fault. An upthrown block between two normal faults dipping away from each other is a horst. The hanging wall will slide upwards right. Its strike and its dip.

A downthrown block between two normal faults dipping towards each other is a graben. Occurs where the hanging wall moves up or is thrust over the foot wall. Low angle normal faults with regional tectonic significance may be designated detachment faults. You probably noticed that the blocks that move on either side of a reverse or normal fault slide up.

The line it makes on the earth s surface is the fault trace. In a normal fault the hanging wall moves downward relative to the footwall. The block below is called the footwall. When the hanging wall moves horizontally it s a strike slipearthquake.

The fault strike is the direction of the line of intersection between the fault plane and earth s surface. Strike slip faults have a different type of movement than normal and reverse faults. Where the fault plane is sloping as with normal and reverse faults the upper side is the hanging wall and the lower side is the footwall. A dip slip fault in which the upper block above the fault plane moves up and over the lower block.

Occurs when the hanging wall moves down relative to the foot wall reverse fault. It is a flat surface that may be vertical or sloping. In fault fault plane is called the hanging wall or headwall. Moving the hanging wall up an inclined fault requires work to overcome friction on the fault and the downward pull of gravity.

If the hanging wall moves to the left the earthquake is called right lateral if it moves to the right it s called a left lateral fault.