Large Earthquake Recurrence In New South Wales: Implications For Earthquake Hazard

The Australian continent is actively deforming at a range of scales in response to far-field stresses associated with plate margins and buoyancy forces associated with mantle dynamics. On the smallest scale (101 km), faultrelated deformation associated with far-field stress partitioning has modified surface topography at rates of up to ~100 m per million years. This deformation is evidenced in both the record of historical earthquakes and in the pre-historic record in the landscape. Palaeoseismological studies indicate that few places in Australia have experienced a maximum magnitude earthquake since European settlement because there are faults in most areas capable of hosting potentially catastrophic earthquakes with magnitudes in excess of 7.0. New South Wales is well represented in terms of its pre-historic earthquake record. Seismogenic faulting in the last 5-10 million years is thought to be responsible for locally generating up to 200 m of the contemporary topographic relief of the Eastern Highlands. Faults west of Sydney belonging to the Lapstone Structural Complex, and faults beneath the greater Sydney region, are associated with infrequent damaging earthquakes. Therefore, decisions relating to the siting and construction of the built environment should be informed using knowledge of local neotectonics.