Product catalogue
An updated National Seismic Hazard Assessment for Australia: Are we designing for the right earthquakes?
Geoscience Australia (GA) has embarked on a project to update the seismic hazard model for Australia through the National Seismic Hazard Assessment (NSHA18) project. The draft NSHA18 update yields many important advances on its predecessors, including: 1) calculation in a full probabilistic framework using the Global Earthquake Model’s OpenQuake-engine; 2) consistent expression of earthquake magni-tudes in terms of moment magnitude, MW; 3) inclusion of epistemic uncertainty through the use of alterna-tive source models; 4) inclusion of a national fault-source model based on the Australian Neotectonic Features database; 5) the use of modern ground-motion models; and 6) inclusion of epistemic uncertainty on seismic source models, ground-motion models and fault occurrence and earthquake clustering models.
The draft NSHA18 seismic design ground motions are significantly lower than those in the current (1991-era) AS1170.4–2007 hazard map at the 1/500-year annual ground-motion exceedance probability (AEP) level. However, draft values at lower probabilities (i.e., 1/2475-year AEP) are entirely consistent, in terms of the percentage area of land mass exceeding different ground-motion thresholds, with other Stable Continental Regions (e.g., central & eastern United States). The large reduction in seismic hazard at the 1/500-year AEP level has led to engineering design professionals questioning whether the new draft design values will provide enough structural resilience to potential seismic loads from rare large earthquakes. This process underscores the challenges in developing national-scale probabilistic seismic hazard analyses (PSHAs) in slowly-deforming regions, where a 1/500-year AEP design level is likely to be much lower than the ANCOLD Maximum Credible Earthquake (MCE) ground motions. Consequently, a robust discussion among the Standards Australia code committee, hazard practitioners and end users is required to consider alternative hazard and/or risk objectives for future standards.
Site-specific PSHAs undertaken for owners and operators of extreme and high consequence dams generally require hazard evaluations at lower probabilities than for typical structural design as recommended in AS1170.4. However, modern national assessments, such as the NSHA18, can provide a benchmark in terms of recommended seismicity models, fault-source models, ground-motion models, as well as hazard values, for low-probability site-specific analyses. With a new understanding of earthquake processes in Australia leading to lower ground-motion hazard values for higher probability events (e.g., 1/500-year AEP), we should also ask whether the currently recommended design probabilities provide an acceptable level of seismic resilience to critical facilities (such as dams) and regular structures.
Abstract presented at the 2017 Australian National Committee on Large Dams (ANCOLD) Conference
Simple
Identification info
- Date (Creation)
- 2017-09-01T00:00:00
- Date (Publication)
- 2024-03-19T22:33:31
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/113462
- Cited responsible party
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Role Organisation / Individual Name Details Publisher Commonwealth of Australia (Geoscience Australia)
Voice Author Allen, T.
Place and Communities Internal Contact Author Griffin, J.
Place and Communities Internal Contact Author Leonard, M.
External Contact Author Clark, D.
Place and Communities Internal Contact Author Ghasemi, H.
Place and Communities Internal Contact
- Issue identification
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Australian National Committee on Large Dams (ANCOLD) 2017 Conference, 26-27 October 2017 Hobart, TAS
- Purpose
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Conference Paper for 2017 Australian National Committee on Large Dams (ANCOLD) Conference
- Status
- Completed
- Point of contact
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Resource provider Place and Communities Division
External Contact Point of contact Allen, T.
Place and Communities Internal Contact
- Spatial representation type
- Grid
- Topic category
-
- Geoscientific information
Extent
Extent
))
- Maintenance and update frequency
- As needed
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
- theme.ANZRC Fields of Research.rdf
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EARTH SCIENCES
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- Keywords
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probabilistic seismic hazard analysis - PSHA
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- Keywords
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design codes
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- Keywords
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neotectonic faults
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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
- Access constraints
- License
- Use constraints
- License
- Other constraints
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© Commonwealth of Australia (Geoscience Australia) 2017
Resource constraints
- Classification
- Unclassified
- 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 Proceedings (page 248)
Link to Conference Proceedings (page 248)
- Distribution format
-
- OnLine resource
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Link to Abstract
Link to Abstract
- Distribution format
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Resource lineage
- Statement
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Conference Paper for 2017 Australian National Committee on Large Dams (ANCOLD) Conference
- Hierarchy level
- Model
Metadata constraints
- Classification
- Unclassified
Metadata
- Metadata identifier
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urn:uuid/80b86f4c-368b-4370-8fdd-72abcde3400d
- Title
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GeoNetwork UUID
- Contact
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Owner Allen, T.
Place and Communities Internal Contact Point of contact Allen, T.
Place and Communities Internal Contact
Type of resource
- Resource scope
- Document
- Name
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Conference Abstract
Alternative metadata reference
- Title
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Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/113462
- Metadata linkage
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https://internal.ecat.ga.gov.au/geonetwork/srv/eng/search?uuid=80b86f4c-368b-4370-8fdd-72abcde3400d
Point-of-truth metadata URL
- Date info (Creation)
- 2017-09-01T07:27:20
- Date info (Revision)
- 2018-03-01T04:10:38
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
- Edition date
- 2015-07-01T00:00:00
- Title
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Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
- Edition
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Version 2.0, April 2015