Product catalogue
THE 2023 UPDATE TO THE AUSTRALIAN NATIONAL SEISMIC HAZARD ASSESSMENT (NSHA23) - PHILOSOPHY AND MODEL CHANGES
<div>The Australian National Seismic Hazard Assessment (NSHA) was updated in 2023 to coincide with the revision of the Australian Standard for the structural design actions for earthquake (AS1170.4). This updates the 2018 NSHA (NSHA18), which applied globally accepted, best-practice probabilistic approaches and yielded considerably lower hazard estimates at the 1/500 annual exceedance probability relative to previous national assessments and the AS1170.4–2007 seismic design values. Whilst the science underpinning the NSHA18 has withstood on-going peer review and critique, Geoscience Australia has reflected on this model and has advocated for adjustments to modelling choices where warranted. The use of structured expert elicitation was a major advance in the development of the NSHA18 and promoted ownership of the model amongst the Australian seismological community. However, some consequences of the modelling choices made during that process were not fully appreciated at the time. The 2023 NSHA (NSHA23) was intended to be a modest update to the 2018 model and again is characterised through structured expert elicitation. However, there are some key changes to the earthquake catalogue, which include: 1) the inclusion of events from mid-2017 through to the end of 2022; 2) the recalculation of local magnitudes for recent events (2010 onwards) to resolve recently discovered inconsistent observatory practice by different Australian monitoring agencies and errors with station metadata, and; 3) the subsequent revision of local magnitude to moment magnitude conversions. All seismic source models in the updated NSHA23 that rely on the updated earthquake catalogue (pre-instrumental and instrumental) are updated to reflect these changes. Incremental updates to the fault-source model and changes to the relative weights between different source-model class types have also been implemented. Another significant advance is the augmentation of the Australian Ground-Motion Database with new and legacy data. High-quality data acquired from Australian earthquakes since 2018 were used to enable more informed choices for the ground-motion characterisation model. In summary, the 2023 updates to the instrumented earthquake catalogue have led to reduced earthquake rates and seismic hazard. This change is counteracted using an updated suite of ground-motion models. Adjustments to weights in the source characterisation model yield spatially variable changes in hazard, most commonly leading to modest increases in hazard.
Presented at the 2024 18th World Conference on Earthquake Engineering, Milan, Italy
Simple
Identification info
- Date (Creation)
- 2023-10-20T20:00:00
- Date (Publication)
- 2025-02-18T06:09:50
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/148987
- Cited responsible party
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Role Organisation / Individual Name Details Publisher Commonwealth of Australia (Geoscience Australia)
Voice Author Allen, T.
Internal Contact Author Griffin, J.
Internal Contact Author Clarke, J.
Internal Contact Author Cummins, P.
Internal Contact Author Ghasemi, H.
Internal Contact Author Ebrahimi, R.
External Contact Author Martin, S.
Internal Contact
- Name
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18th World Conference on Earthquake Engineering (WCEE 2024) 30 June - 5 July 2024 Milan, Italy
- Purpose
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2024 World Conference on Earthquake Engineering paper
- Status
- Completed
- Point of contact
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Role Organisation / Individual Name Details Resource provider Place and Communities Division
External Contact Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Allen, T.
Internal Contact
- Spatial representation type
- Topic category
-
- Geoscientific information
Extent
))
- Maintenance and update frequency
- Not planned
Resource format
- Title
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Product data repository: Various Formats
- Website
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Data Store directory containing the digital product files
Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes
- Project
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seismic hazard
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- Project
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ground motion model
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- Project
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earthquake catalogue
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- Keywords
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seismic hazard
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- Keywords
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ground motion model
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- Keywords
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earthquake catalogue
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- theme.ANZRC Fields of Research.rdf
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Seismology and seismic exploration
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- Keywords
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Published_External
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Resource constraints
- Title
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Creative Commons Attribution 4.0 International Licence
- Alternate title
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CC-BY
- Edition
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4.0
- Addressee
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Role Organisation / Individual Name Details User Any
- Use constraints
- License
- Use constraints
- Other restrictions
- Other constraints
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© Commonwealth of Australia (Geoscience Australia) 2024
Resource constraints
- Title
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Australian Government Security Classification System
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
- Classification system
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Australian Government Security Classification System
Associated resource
- Association Type
- Had derivation
- Title
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The 2023 National Seismic Hazard Assessment for Australia. Model Overview
- Citation identifier
- 148969
- Citation identifier
- 86d9ffcf-8bbf-4aad-b6c4-70fcae2be457
- Language
- English
- Character encoding
- UTF8
Distribution Information
- Distributor contact
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Role Organisation / Individual Name Details Distributor Commonwealth of Australia (Geoscience Australia)
Voice facsimile
- OnLine resource
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Link to Conference Page
Link to Conference Page
- Distribution format
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- OnLine resource
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Link to Paper
Link to Paper
- Distribution format
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Resource lineage
- Statement
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<div>Summary of GA Record "The 2023 National Seismic Hazard Assessment for Australia: Hazard Design Factors Proposed for the Update to the Australian Standard AS 1170.4" (eCat 148969)</div>
Metadata constraints
- Title
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Australian Government Security Classification System
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Metadata
- Metadata identifier
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urn:uuid/51c79b0e-7063-45f1-9ed1-11e610652563
- Title
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GeoNetwork UUID
- Language
- English
- Character encoding
- UTF8
- Contact
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Allen, T.
Internal Contact
Type of resource
- Resource scope
- Document
- Name
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Journal Article / Conference Paper
Alternative metadata reference
- Title
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Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/148987
- Date info (Creation)
- 2025-02-18T05:59:27
- Date info (Revision)
- 2025-02-18T05:59:27
Metadata standard
- Title
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AU/NZS ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-3
- Title
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Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
- Edition
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Version 2.0, September 2018
- Citation identifier
- http://pid.geoscience.gov.au/dataset/ga/122551