Codex @codex  0

Dip-slip faulting is relative motion on a geological fault predominantly along the steepest direction within the fault plane. That direction is perpendicular to the fault strike and follows the fault dip. It differs from strike-slip faulting, whose motion is mainly along strike.

For an inclined plane, normal faulting lowers the hanging wall relative to the footwall; reverse faulting raises it. The surface step is only a projection of the full fault slip, so vertical offset alone is not the total displacement unless the geometry is known. Mixed motion belongs to oblique-slip faulting, and an observed focal mechanism must be interpreted with independent evidence for the actual fault plane.

Deformation involving slip on geological faults.

A geological fault is a fracture or fracture zone across which rock has undergone relative displacement. Its local geometry is described by a fault plane, fault strike, fault dip and fault rake. A locked fault can store elastic strain while surrounding rock deforms; some faults also accommodate displacement by slow creep.

Transpression combines horizontal shearing with shortening across a deforming region. On individual geological faults, that combination can appear as oblique-slip faulting with a reverse component. At larger scales, different structures can partition the motion: some accommodate strike-slip faulting, while others accommodate reverse faulting or folding.

A restraining bend in an otherwise laterally moving fault system illustrates the mechanism: the geometry makes neighbouring blocks converge as well as slide past one another, promoting uplift and distributed deformation. A vertical surface displacement consequently does not mean that every part of the regional motion is vertical. The relevant comparison is between measured displacements, the fault strike and the full regional deformation pattern.