South West seismic zone

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The South West seismic zone (also identified as SWSZ) is a major intraplate earthquake province located in the south west of Western Australia. [1] [2] [3]

Contents

It was known earlier as the Yandanooka–Cape Riche Lineament, [4] including the physiographic boundary known as the Meckering Line, and also the junction between Swanland[ clarification needed ] and Salinaland[ clarification needed ]. [5] [6]

The zone exists within an Archaean Shield structure called the Yilgarn Block. [7] The identified geological subdivisions within this Precambrian structure do not show an obvious relation to the seismicity. [8]

The zone represents a significant seismic hazard to Perth. [2] More than six thousand earthquakes have occurred in the SWSZ in the years 1968 – 2002. [8] Meckering, Cadoux and Burakin earthquakes originated in the SWSZ. More recent events have occurred to the south in Lake Muir in 2018 [9] [10] [11] [12] and Arthur River in 2022. [13]

The zone and the explanation of it, has been titled Perthquake in the Catalyst programme on the ABC in 2001. [14]

Temporal variation of the events in the region have been analysed over time. [15] [16] In the 2000s, monitoring and instrumentation was developed in the region. [17] [18]

Notes

  1. ↑ First named by H.A.Doyle (1971) Seismicity and Structure in Australia Royal Society of New Zealand Bulletin Vol.9 pp. 149–152
  2. 1 2 Leonard, M; Darby, D; Hu, G (2007). GPS-geodetic monitoring of the South West Seismic Zone of Western Australia: progress after two observation epochs in 2002 and 2006 (PDF). Australian Earthquake Engineering Society 2007, Wollongong. Archived (PDF) from the original on 20 July 2008. Retrieved 2 June 2019. The Australian southwest seismic zone (SWSZ) is a north-south trending belt of intra-plate earthquake activity that occurs in the southwest of Western Australia, bounded by 30.5°S to 32.5°S and 115.5°E to 118°E. This is one of the most seismically active areas in Australia, with nine earthquakes over magnitude 5.0 occurring between 1968 and 2002; the largest of these was the M6.8 Meckering earthquake in 1968. Since the SWSZ lies as close as ~150 km from the ~1.4 million population of the Perth region, it poses a distinct seismic hazard.
  3. ↑ Featherstone, W.E; Penna, N.T; Leonard, M; Clark, D; Dawson, J; Dentith, Mike; Darby, D; Mccarthy, R (2004), GPS-geodetic deformation monitoring of the south-west seismic zone of Western Australia : review, description of methodology and results from epoch-one, ISSN   0035-922X
  4. ↑ Fairbairn, David (16 October 1968), W.A. earthquake equals Australia's biggest ever , retrieved 1 September 2023
  5. ↑ Geological Survey of Western Australia (1975), The Geology of Western Australia, Western Australia Geological Survey, ISBN   978-0-7244-6084-7 – section Southwestern Province by I.R. Williams page 65
  6. ↑ Dent, V. F. (Victor Francis); Australia. Bureau of Mineral Resources, Geology and Geophysics (1989), Computer generated crustal models for the south west seismic zone Western Australia, Bureau of Mineral Resources, Geology & Geophysics, retrieved 1 September 2023
  7. ↑ Geological Survey of Western Australia (1975), The Geology of Western Australia, Western Australia Geological Survey, ISBN   978-0-7244-6084-7 – section Yilgarn Block by I.R. Williams pages 33–81 – now called Yilgarn Craton
  8. 1 2 "School of Earth Sciences | Science".
  9. ↑ "Magnitude-5.7 earthquake rocks southern WA". Australian Broadcasting Corporation. 17 September 2018. Retrieved 9 November 2018.
  10. ↑ "Magnitude-4.7 earthquake rocks area surrounding Lake Muir in WA's Great Southern". Australian Broadcasting Corporation. 13 October 2018. Retrieved 9 November 2018.
  11. ↑ Ben Anderson (9 November 2018). "Earthquake at Lake Muir shakes Perth and WA's South West". News Corporation . Retrieved 9 November 2018.
  12. ↑ "Recent Earthquakes Lake Muir area,WA". Geoscience Australia . Retrieved 12 November 2018.
  13. ↑ "Earthquake 'swarm' rattles WA's south with more than 40 over three weeks". Australia: ABC News. 24 January 2022. Retrieved 25 January 2022.
  14. ↑ http://www.abc.net.au/catalyst/stories/s392312.htm PerthQuake
  15. ↑ M.O. Michael-Leiba Temporal variation in seismicity of the Southwest Seismic Zone, Western Australia: implications for earthquake risk assessment, Geoscience Australia
  16. ↑ Geological Society of Australia. Specialist Group on Solid-Earth Geophysics (3 June 1996), "Crustal Structure In The Southwest Yilgarn Craton, Western Australia – An Explanation For The Southwest Seismic Zone? (3 June 1996)", Geophysics Down Under: Newsletter of the Specialist Group on Solid-Earth Geophysics (23), Geological Society of Australia. Specialist Group on Solid-Earth Geophysics: 4, ISSN   1035-0853
  17. ↑ Dent, Victor; Harris, P; Hardy, D (2010), A new seismograph network in the southwest seismic zone of Western Australia, Australian Earthquake Engineering Society, ISBN   978-0-9807420-2-2
  18. ↑ Reading, AM; Kennett, BLN; Dentith, MC (2003), "Seismic structure of the Yilgarn Craton, Western Australia", Australian Journal of Earth Sciences, 50 (3): 427, Bibcode:2003AuJES..50..427R, doi:10.1046/j.1440-0952.2003.01000.x, S2CID   10466512 , retrieved 30 October 2021

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References

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