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The 2018 National Seismic Hazard Assessment: Model overview

Created 17/10/2025

Updated 17/10/2025

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Geoscience Australia, together with contributors from the wider Australian seismology community, has produced a National Seismic Hazard Assessment (NSHA18) that is intended as an update to the 2012 National Seismic Hazard Maps (NSHM12; Burbidge, 2012; Leonard et al., 2013). This Geoscience Australia Record provides an overview of the development of the NSHA18. Time-independent, mean seismic design values are calculated on Standards Australia’s AS1170.4 Soil Class Be (at VS30=760 m/s) for the horizontal peak ground acceleration (PGA) and for the geometric mean of the spectral accelerations, Sa(T), for T = 0.1, 0.2, 0.3, 0.5, 1.0, 2.0 and 4.0 s over a 15-km national grid spacing. Hazard curves and uniform hazard spectra are also calculated for key localities. Maps of PGA, in addition to Sa(0.2 s) and Sa(1.0 s) and for a 10% probability of exceedance in 50 years (Figure A). Additional maps and seismic hazard products are provided in a separate Geoscience Australia Record (Allen, 2018). The NSHA18 update yields many important advances over its predecessors, including: - the calculation in a full probabilistic framework (Cornell, 1968) using the Global Earthquake Model Foundation’s OpenQuake-engine (Pagani et al., 2014); - the consistent expression of earthquake magnitudes in terms of moment magnitude, MW; - inclusion of a national fault-source model based on the Australian Neotectonic Features database (Clark et al., 2016); - the inclusion of epistemic (i.e. modelling) uncertainty: - through the use of multiple alternative source models; - on magnitude-recurrence distributions; - fault recurrence and clustering models; - on maximum earthquake magnitudes for both fault and area sources through an expert elicitation workshop; and - the use of modern ground-motion models, capturing the epistemic uncertainty on ground motion through an expert elicitation workshop.

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Additional Info

Field Value
Title The 2018 National Seismic Hazard Assessment: Model overview
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/616e7b5f-f8f8-4e95-9baf-eb06815e7e5b
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period
Geospatial Coverage
Map data © OpenStreetMap contributors
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        112.0,
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      ],
      [
        154.0,
        -44.0
      ],
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      ],
      [
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      ],
      [
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      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "The 2018 National Seismic Hazard Assessment: Model overview". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/the-2018-national-seismic-hazard-assessment-model-overview