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An exposed fault plane revealed as fault slip, differential motion and removal of cover bring it to the surface. On a normal fault, lowering the hanging wall can expose a planar footwall face. Continued exposure may preserve a bedrock scarp while weathering, erosion and collapse progressively modify its older portions. A hillslope following the plane therefore need not be an independent erosional surface that accidentally has the same orientation.

The visible surface can be an exhumed fault surface, rather than an unrelated hillslope that happens to intersect a buried plane. Downward motion of the hanging wall exposes the footwall face; repeated displacement and removal of loose material can reveal a substantial length of the same fault plane. Where exposure is renewed faster than weathering, erosion and collapse erase it, that planar surface remains part of the hillside. The less weathered lower face and rougher, vegetated upper ground are consistent with differential exposure, though the photograph alone does not date individual events.

At greater distance or over longer times, erosion modifies the slope and the hillside will cross or obscure the fault plane. The correspondence is therefore a transient competition between fault slip, exhumation and surface processes, not a requirement that all hillslopes follow faults.

Physical breakdown or chemical alteration of rock at or near the surface. Distinguish in-place weathering from transport by erosion. Chemical weathering changes mineral composition, whereas physical processes can fragment rock without requiring the same chemical transformations.