Can trishear explain strain distribution in syn-tecontic sedimentary growth faults: evidence from deep water Niger Delta?

This study uses a 3D seismic reflection volume, courtesy of CGG Veritas, in the deepwater fold and thrust belt of the Niger delta to investigate variations in strain distribution between pre-tectonic and syn-tectonic sedimentary strata. Two en-echelon reverse faults and associated pre and syn-tectonic strata are evident. Despite opposing polarity both faults have similar fault geometry, limb angle (30°) and a reduction of fault displacement from ca. 700 m to zero in the zone of en-echlon overlap. Furthermore, in the pre-tectonic strata both faults are characterized by an abrupt termination of seismic reflections along a narrow zone (ca. 100 m) with little or no deformation within hangingwall or footwalls. In contrast, within the syn-tectonic package variations in reflection characeter suggest heterogenous strain and significant deformation of both hangingwall and footwall within a triangular zone. The application of trishear reproduces the observed fault and stratal geometries and variations in strain distribution associated wtih the stratigraphic variations. In addition, trishear successfully results in a line balance section