= Solution
A <blind reverse fault> can transfer displacement into <folding> above its buried tip. Look for an asymmetric growing <anticline>, often with a steep forelimb and gentler backlimb, aligned with the inferred <fault strike>. A <fault-propagation fold> is one possible geometry; the fold alone does not uniquely establish the fault's depth or shape. Exposed older <geological strata> may be more steeply tilted than younger deposits, while <growth strata> thin and onlap toward an uplifting crest or fan in dip as deformation accumulates. Progressive <unconformities> and warped young deposits help distinguish active folding from an inherited fold.
In the landscape, seek an elongate uplifted ridge, warped or tilted <river terraces> and <alluvial fans>, localized <fold scarps>, incision across the rising structure, and drainage deflection or abandoned channels. Compare landforms of known relative ages: increasing deformation with age records repeated motion. Opposite fold limbs may show contrasting uplift and tilting, while active axial surfaces can concentrate deformation into narrow belts even without the main <fault> reaching the surface. Combine geological mapping and dating with <seismic reflection> or evidence from <geodesy> where available; an erosional ridge alone is not proof of a buried active reverse fault.<Blind-thrust mapping report by United States Geological Survey>[Sections “Active fold scarp” and “Syncline axis corresponding to the base of a fold forelimb”: surface folding and scarps can locate deformation associated with buried thrust tips.]{ref}
Back to article page
