Tamarah King, Mark Quigley, Dan Clark

The 23rd March 2012 Mw 5.2 Pukatja earthquake produced an arcuate surface rupture 1.6 km long with a maximum vertical offset of 0.48 m. We reclassify its length to 1 km based on application of orientation and kinematic criteria used previously to measure other historic Australian surface ruptures. Epicentres are poorly constrained and inaccurate, located up to 17 km from the surface rupture with no reported uncertainties. Published interpretations of available seismological data do not provide constraints on rupture processes, hypocentre depth, and fault geometry. Sections of the surface rupture match the strike and dip of an intrusive contact as mapped in the field < 500 m from the rupture. This feature is evident as a linear magnetic anomaly co-located and parallel to the surface rupture, suggesting a strong bedrock control on the location and orientation of surface rupture. There is no topographic expression of prior rupture, and a shallow hand-dug trench shows evidence of only the historic rupture. However, erosion rates estimates suggest that residency time of any prior ruptures in the landscape may have been < 50 kyrs, and hence topographic evidence may have been removed prior to deposition of overlying sediments. Investigations of rock falls surrounding the historic rupture may provide estimates of strong ground motion recurrence in the absence of other paleoseismic data.