Late Quaternary movement on White Creek Fault, South Island, New Zealand

Abstract

The faulted Buller River terrace sequence at White Creek Fault is the best locality to document the faulting that occurred during the Murchison earthquake of 17 June 1929. The upper faulted tread at White Creek is correlated with the later Otiran aggradation surface of the Buller valley. Riser height consistency and constant scarp height on all terrace treads, and a planar granite platform, are consistent with one single fault movement since the aggradation surface formed c. 18 000 y. ago. Tree-ring dating of Nothofagus fusca trees that were growing on the fault scarp indicates a significant event in 1929 and is attributed to the faulting during the Murchison earthquake. Periodicity of faulting at two Buller-NW Nelson reverse faults—Inangahua Fault and White Creek Fault—is found to be longer than 6000 y., about one order of magnitude longer than for faults within the shear belt of New Zealand.