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.
Shortening accommodated by a hanging wall moving up relative to the footwall. The centre of its dip-slip focal mechanism is compressional under the usual lower-hemisphere convention. Low-angle reverse faulting is commonly called thrust faulting.
A fault on which the hanging wall moves up relative to the footwall, accommodating shortening. A low-angle reverse fault is a thrust fault. The fault dip is a geometric property and should be distinguished from the direction of fault slip.
A low-angle reverse fault. Near-surface splays may accompany either a surface-breaking or a blind main rupture.
A mechanically weak detachment along which an overlying package can move relative to its substrate. A décollement can follow weak bedding and connect to steeper thrust ramps, so its orientation need not equal the optimum dip for a new fracture in homogeneous rock.
A reverse fault dipping oppositely to the dominant thrust system and accommodating part of its shortening.
A fault with reverse slip whose upper tip remains beneath the ground surface. It can deform the overburden through folding, localized fold scarps, and secondary faults.
Extension accommodated by a hanging wall moving down relative to the footwall. Its focal mechanism has an extensional dip-slip pattern, with the centre unshaded under the convention that shaded quadrants denote compression.
A tilted region transferring displacement between overlapping normal fault segments. Opposing gradients of fault throw can produce an unbroken ramp. Continued extension can breach the ramp with a connecting fault, generating a linked segmented trace.
A relatively down-dropped block bounded by opposing normal faults. A small secondary graben can form within the distributed surface rupture zone of one earthquake.
A fault on which the hanging wall moves downward relative to the footwall. Local bending or collapse can create small normal faults even during a regional reverse-faulting event.
A long-lived low-angle normal fault that can exhume deep crust or mantle. Its mapped scarp need not be a plate-motion arrow.
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