Product catalogue
Apples and Oranges: Developing a consistent catalog of local magnitudes for the National Seismic Hazard Assessment of Australia
Modern probabilistic seismic hazard assessments rely on earthquake catalogs consistently expressed in terms of moment magnitude, MW. However, MW is still not commonly calculated for small local events by many national networks. The preferred magnitude type calculated for local earthquakes by Australia’s National Earthquake Alerts Centre is local magnitude, ML. For use in seismic hazard forecasts, magnitude conversion equations are often applied to convert ML to MW. Unless these conversions are time-dependent, they commonly assume that ML estimation has been consistent for the observation period. While Australian-specific local magnitude algorithms were developed from the late 1980s and early 1990s, regional, state and university networks did not universally adopt these algorithms, with some authorities continuing to use Californian magnitude algorithms. Californian algorithms are now well-known to overestimate earthquake magnitudes for Australia. Consequently, the national catalogue contains a melange of contributing authorities with their own methods of magnitude estimation.
The challenge for the 2018 National Seismic Hazard Assessment of Australia was to develop a catalog of earthquakes with consistent local magnitudes, which could then be converted to MW. A method was developed that corrects magnitudes using the difference between the original (inappropriate) magnitude formula and the Australian-specific corrections at a distance determined by the nearest recording station likely to have recorded the earthquake. These corrections have roughly halved the rates of ML 4.5 earthquakes in the Australian catalogue.
To address ongoing challenges for catalog improvement, Geoscience Australia is digitising printed and hand-written observations preserved on earthquake data sheets. Once complete, this information will provide a valuable resource that will allow for further interrogation of pre-digital data and enable refinement of historical catalogs.
Presented at the 2019 Seismological Society of America Conference, Seattle in the special session on “Seismology BC(d)E: Seismology Before the Current (digital) Era”
Simple
Identification info
- Date (Creation)
- 2019-01-08T00:00:00
- Date (Publication)
- 2024-03-20T05:19:32
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/126245
- 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 Moseley, A.
Place and Communities Internal Contact
- Name
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Seismological Society of America Conference (SSA), 23-26 April 2019, Washington, USA
- Purpose
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Abstract for submission to the 2019 Seismological Society of America 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
- 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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- Theme
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earthquake catalogue
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- Theme
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seismic hazard
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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
-
4.0
- Access constraints
- License
- Use constraints
- License
- Other constraints
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© Commonwealth of Australia (Geoscience Australia) 2019
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 Page
Link to Conference Page
- Distribution format
-
- OnLine resource
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Link to Abstract (page 271)
Link to Abstract (page 271)
- Distribution format
-
Resource lineage
- Statement
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Abstract for submission to the 2019 Seismological Society of America Conference
- Hierarchy level
- Dataset
Metadata constraints
- Classification
- Unclassified
Metadata
- Metadata identifier
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urn:uuid/3cc476e1-e8d0-46c7-bb46-425a3732d469
- 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/126245
- Metadata linkage
-
https://ecat.ga.gov.au/geonetwork/srv/eng//metadata/0d49a5b8-d908-4450-af8e-0afa05948e55
- Metadata linkage
-
https://ecat.ga.gov.au/geonetwork/srv/eng//metadata/3cc476e1-e8d0-46c7-bb46-425a3732d469
- Date info (Creation)
- 2019-01-10T04:05:32
- Date info (Revision)
- 2019-01-10T04:05:32
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