Geometrically coherent continuous deformation in the volume surrounding a seismically imaged normal fault-array
We calculated an apparent dip attribute, which was used to ascertain the spatial distribution of fault-related continuous deformation. The vertical component of displacement calculated from the continuous deformation acts to fill-in missing displacement in the fault-throw profile. This result shows that apparently complex 3D patterns of continuous strain in the volumes surrounding the fault-array developed as part of a single, geometrically coherent fault-array. However, if this component of continuous deformation was not added to the throw profile, the fault-array could have been misinterpreted as a series of isolated fault segments with coincidental overlaps. This technique permits the analysis of continuous deformation structures, which are up to an order of magnitude smaller than previously described. In the study area, these structures are interpreted as small fault-propagation folds, forming in a shale-dominated cover sequence. The fault-propagation folds above the upper tip line of the mapped fault-array bifurcate upwards from the fault surface into three coherent lobes and resemble secondary fault segments. The near-constant along-strike length of the region of continuous deformation throughout the syn-rift sequence implies that the length of the fault-array was established at an early stage in its growth, prior to the establishment of a seismically-visible fault surface.