Abstract - Detailed kinematic analysis of a large (1650 m maximum displacement) reactivated normal
fault in the Taranaki Basin, New Zealand, has been conducted using high quality 3D seismic data. The
Parihaka Fault is approximately north-south striking in basement, where it accrued Late Cretaceous to
Early Eocene displacements in response to east-west extension, and was obliquely reactivated by NWSE
extension in the Pliocene. Reactivation resulted in upward propagation, newly formed segmentation
and updip clockwise rotation of the fault surface by up to ~20° from the strike of the basement fault.
Fault segmentation, and map-view soft-linkage by relay zones in post Miocene strata, was synchronous
with the formation of antithetic faults in Late Miocene strata at bends in the fault surface. Fault
segment lengths, antithetic faults and relay zone dimensions were formed geologically instantaneously
during initial reactivation of the main fault at 3.7-3.4 Ma (i.e. within the first ~10% of faulting). Rapid
formation of Pliocene fault segments is followed by displacement accumulation without an increase in
fault segment length until eventual relay breaching when continued ramp rotation is unsustainable.
This evolutionary history is consistent with a model in which arrays of fault segments are, from
inception, components of a single coherent structure.
Journal of Structural Geology, 39, 253-267, 2012.