South West Seismic Zone
Introduction The '''South West Seismic Zone''' (also identified as SWSZ) is a major intraplate earthquake province located in the south west of Western Australia.It was known earlier as the '''Yandanooka–Cape Riche Lineament''', including the physiographic boundary known as the '''Meckering Line''', and also the junction between Swanland and Salinaland. The zone exists within an Archaean Shield structure called the Yilgarn Block. The identified geological subdivisions within this Precambrian structure do not show an obvious relation to the seismicity.The zone represents a significant seismic hazard to Perth. More than six thousand earthquakes have occurred in the SWSZ in the years 1968 – 2002.Meckering, Cadoux and Burakin earthquakes originated in the SWSZ. More recent events have occurred to the south in Lake Muir in 2018 and Arthur River in 2022.The zone and the explanation of it, has been titled ''Perthquake'' in the ''Catalyst'' programme on the ABC in 2001.Temporal variation of the events in the region have been analysed over time.In the 2000s, monitoring and instrumentation was developed in the region.
Table of earthquakes List of earthquakes of magnitude 4 or more in Southwestern Australia 1920–1961(based in part on the records of Perth Observatory 1923–1959 andMundaring Geophysical Observatory 1959–1980).DateOrigin timeEpicentre(lat., S)Epicentre(long., E)Local magnitudeLocation8 February 1920  05:24  35.00  111.00   6.2   260 km south west of Cape Leeuwin18 December 1940  21:45  32.20  117.20  4.2  Beverley, Brookton19 April 1946  21:13  38.5  114.5  5.7  West of Yallingup17 September 1946  15:12  32.5  116.9  4.5  Pingelly2 May 1949  10:00  30.90  116.40  5.1  Yerecoin7 May 1949  17:09  30.90  116.40  4.1  Yerecoin11 March 1952  06:09  31.30  116.50  5.1  Bolgart27 November 1954  08:36  32.00  116.7  3.9  Talbot Brook29 April 1955  09:14  30.90  116.40  4.7  Yerecoin29 April 1955  19:49  30.90  116.40  4.4  Yerecoin29 August 1955  06:09  30.70  116.40  5.3  Gabalong30 August 1955  13:52  30.70  116.40  5.8  Gabalong30 August 1955  14:07  30.70  116.40  4.7  Gabalong30 August 1955  16:46  30.70  116.40  4.6  Gabalong24 February 1956  06:27  30.9  116.4  4.5  Yerecoin5 April 1956  23:13  30.9  116.4   4.5  Yerecoin20 March 1958  03:03  32.20  117.20  4.8  Beverley, Brookton3 October  1959  12:07:22.0 34.50  114.50  4.2  55 km SW Cape Leeuwin12 June 1961  18.00:51.0  34.20  114.50  4.1  50 km SW Cape Leeuwin
Notes
See also * Earthquakes in Western Australia
References * Featherstone, Will (1998) ''Geodetic monitoring of the South West Seismic Zone'' paper at Curtin University of Technology 24 25 September 1998 to the Advances in Deformation Monitoring International Workshop
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