Temporal variation in seismicity of the Southwest Seismic Zone, Western Australia: implications for earthquake risk assessment

In the area 30-33°S, 116-118°E of the Southwest Seismic Zone of Western Australia, ML -4.0 earthquakes for the period 1960-1983 do not fit a Poisson model. However, when foreshocks and aftershocks are excluded, the hypothesis of a Poisson distribution cannot be rejected for the resulting series of main shocks. A similar result holds for the subset of ML -5.0 events for the period 1949- 1983. Consequently, when earthquake risk is being assessed by methods that assume a Poisson distribution, foreshocks and aftershocks should be excluded . However, the consequent apparent reduction of risk caused by removing these potentially damaging earthquakes should be pointed out. Although records of seismicity are probably incomplete for the early part of this century, there appears to have been an increase in numbers of ML -4.0 events, starting around 1949. Although, the data are too uncertain to test the increase in the ML -4.0 main shocks statistically, there has been an approximate five-fold increase in the mean yearly number of ML -4.5 main shocks during the period 1949 to 1983, compared with the period 1923 to 1948. This is clearly larger than would be expected from a Poisson process. Consequently, the apparent increase in the number of ML -4.0 events is probably also real and not an artefact of a Poisson process. Also, there were no ML -5.0 events during the period 1923 to 1948, and the only two ML -6.0 earthquakes this century took place in 1968 and 1979. This increase in seismicity since the late 1940s should be taken into account in the interpretation of earthquake risk calculations.

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Identification info

Date (Publication)
1987-01-01T00:00:00
Citation identifier
Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/81211

Cited responsible party
Role Organisation / Individual Name Details
Publisher

Bureau of Mineral Resources, Geology and Geophysics

 Canberra
Author

Michael-Leiba, M.O.

 1
Name

BMR Journal of Australian Geology and Geophysics

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10:2:133-137

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Corp
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Commonwealth of Australia (Geoscience Australia)
Custodian

Commonwealth of Australia (Geoscience Australia)

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  • Geoscientific information

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E
W


Maintenance and update frequency
Unknown

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Title

Product data repository: Various Formats

Website

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

Keywords

  • GA Publication

  • Journal

Keywords

  • WA

Australian and New Zealand Standard Research Classification (ANZSRC)

  • Earth Sciences

Keywords

  • Published_External

Resource constraints

Title

Creative Commons Attribution 4.0 International Licence

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CC-BY

Edition

4.0

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http://creativecommons.org/licenses/

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License

Resource constraints

Title

Australian Government Security ClassificationSystem

Edition date
2018-11-01T00:00:00
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https://www.protectivesecurity.gov.au/Pages/default.aspx

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Unclassified
Language
English
Character encoding
UTF8

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Commonwealth of Australia (Geoscience Australia)

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OnLine resource

Journal article (pdf)

Journal article (pdf)

Distribution format

  • pdf

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Unknown

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Non geographic dataset
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GA Publication

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Source data not available.

Metadata constraints

Title

Australian Government Security ClassificationSystem

Edition date
2018-11-01T00:00:00
Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification
Unclassified

Metadata

Metadata identifier
urn:uuid/fae9173a-7098-71e4-e044-00144fdd4fa6

Title

GeoNetwork UUID

Language
English
Character encoding
UTF8
Contact
Role Organisation / Individual Name Details
Point of contact

Commonwealth of Australia (Geoscience Australia)

 Voice

Type of resource

Resource scope
Document
Name

AGSO BMR Journal

Alternative metadata reference

Title

Geoscience Australia - short identifier for metadata record with

uuid

Citation identifier
eCatId/81211

Metadata linkage

https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/fae9173a-7098-71e4-e044-00144fdd4fa6

Date info (Revision)
2018-04-20T06:08:20
Date info (Creation)
2014-06-03T00:00:00

Metadata standard

Title

AU/NZS ISO 19115-1:2014

Metadata standard

Title

ISO 19115-1:2014

Metadata standard

Title

ISO 19115-3

Title

Geoscience Australia Community Metadata Profile of ISO 19115-1:2014

Edition

Version 2.0, September 2018

Citation identifier
https://pid.geoscience.gov.au/dataset/ga/122551

 
 

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