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.
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