Hanging Wall Faults

Occurs where the hanging wall moves up or is thrust over the foot wall.

Hanging wall faults.

The fault strike is the direction of the line of intersection between the fault plane and earth s surface. The dip of a fault plane is its angle of inclination measured from the horizontal. 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.

Strike slip faults have a different type of movement than normal and reverse faults. A downthrown block between two normal faults dipping towards each other is a graben. The line it makes on the earth s surface is the fault trace. Moving the hanging wall up an inclined fault requires work to overcome friction on the fault and the downward pull of gravity.

In a normal fault the hanging wall moves downward relative to the footwall. Low angle normal faults with regional tectonic significance may be designated detachment 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. The block below is called the footwall.

Its strike and its dip. 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. When the hanging wall moves horizontally it s a strike slipearthquake. Any fault plane can be completely described with two measurements.

When the fault plane is vertical there is no hanging wall or footwall. An upthrown block between two normal faults dipping away from each other is a horst. You probably noticed that the blocks that move on either side of a reverse or normal fault slide up. Occurs when the hanging wall moves down relative to the foot wall reverse fault.

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