The 2018 revision of Australia's National Seismic Hazard Assessment (NSHA) represents a substantial improvement from the 2013 NSHA. In particular, this revision will include active fault models, an improved and more homogeneous earthquake catalogue, and greater epistemic uncertainty through a call for third party source models. This paper presents models of seismicity and ground motion that are currently being developed at Geoscience Australia for the NSHA, as implemented in the OpenQuake software. Weighting of logic tree branches for alternative models are discussed, and how these relate to the fundamental datasets on which they are based. For example, a smoothed seismicity model considers only recent seismicity while source models derived from neotectonic data consider a much longer time history. Final weightings will be determined in consultation with members of the Australian seismological community. This abstract was submitted and presented to the 2016 Australian Earthquake Engineering Society Conference (AEES) ( https://aees.org.au/aees-asian-seismological-commission-conferences/)

The 2018 revision of Australia's National Seismic Hazard Assessment (NSHA18) represents a substantial improvement from the 2013 NSHA. In particular, this revision will include a fault source models, an improved and more homogeneous earthquake catalogue, and greater epistemic uncertainty through a call for third party source models. This paper presents updated models of seismicity and ground motion that are currently being developed at Geoscience Australia for the NSHA. We use the OpenQuake software to calculate seismic hazard for Australia and compare with OpenQuake implementations of third-party models and the 2013 NSHA. Weighting of logic tree branches for alternative models are discussed, and how these relate to the fundamental datasets on which they are based. A smoothed seismicity model is developed based on recent seismicity while source models derived from neotectonic fault data consider a much longer time history. Final weightings, including for third party models, will be determined in consultation with members of the Australian seismological community.