Fluid‐Enhanced Neotectonic Faulting in the Cratonic Lithosphere of the Nullarbor Plain in South‐Central Australia

The Nullarbor Plain is underlain by thick cratonic lithospheric mantle that almost devoid of contemporary seismicity. Analysis high-resolution digital elevation models indicates neotectonic fault-propagation fold traces on the nearly flat karst landscape locally extend to lengths >100 km, suggesting potential for hosting large (>7.3–7.5) moment magnitude earthquakes. Along-strike maximum displacements are not proportional surface trace length but spatially associated with crust-scale electrical conductors identified in magnetotelluric surveys. Two major penetrate from upper crust uppermost (at depths < 60 km) along crustal scale shear zones. Conductivity zones higher than conductivity at increased depth, fluid-enhanced enrichment hydrogen and/or carbon. Lithospheric fluid localization ancient slab subduction hydrothermal alteration may have weakened pre-existing faults and enhanced faulting Plain.