South West Seismic Zone
The South West Seismic Zone is a major intraplate earthquake province located in the south west of Western Australia. It was known earlier as the Yandanooka – Cape Riche Lineament, corresponds to 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.
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.
Table of earthquakes
List of earthquakes of magnitude 4 or more in Southwestern Australia 1920–1961.
| Date | Origin time | Epicentre | Epicentre | Local magnitude | Location |
| 8 February 1920 | 05:24 | 35.00 | 111.00 | 6.2 | 260 km south west of Cape Leeuwin |
| 18 December 1940 | 21:45 | 32.20 | 117.20 | 4.2 | Beverley, Brookton |
| 19 April 1946 | 21:13 | 38.5 | 114.5 | 5.7 | West of Yallingup |
| 17 September 1946 | 15:12 | 32.5 | 116.9 | 4.5 | Pingelly |
| 2 May 1949 | 10:00 | 30.90 | 116.40 | 5.1 | Yerecoin |
| 7 May 1949 | 17:09 | 30.90 | 116.40 | 4.1 | Yerecoin |
| 11 March 1952 | 06:09 | 31.30 | 116.50 | 5.1 | Bolgart |
| 27 November 1954 | 08:36 | 32.00 | 116.7 | 3.9 | Talbot Brook |
| 29 April 1955 | 09:14 | 30.90 | 116.40 | 4.7 | Yerecoin |
| 29 April 1955 | 19:49 | 30.90 | 116.40 | 4.4 | Yerecoin |
| 29 August 1955 | 06:09 | 30.70 | 116.40 | 5.3 | Gabalong |
| 30 August 1955 | 13:52 | 30.70 | 116.40 | 5.8 | Gabalong |
| 30 August 1955 | 14:07 | 30.70 | 116.40 | 4.7 | Gabalong |
| 30 August 1955 | 16:46 | 30.70 | 116.40 | 4.6 | Gabalong |
| 24 February 1956 | 06:27 | 30.9 | 116.4 | 4.5 | Yerecoin |
| 5 April 1956 | 23:13 | 30.9 | 116.4 | 4.5 | Yerecoin |
| 20 March 1958 | 03:03 | 32.20 | 117.20 | 4.8 | Beverley, Brookton |
| 3 October 1959 | 12:07:22.0 | 34.50 | 114.50 | 4.2 | 55 km SW Cape Leeuwin |
| 12 June 1961 | 18.00:51.0 | 34.20 | 114.50 | 4.1 | 50 km SW Cape Leeuwin |
| 16 September 2018 | 5.7 | Lake Muir | |||
| 13 October 2018 | 4.7 | Lake Muir | |||
| 9 November 2018 | 5.07am | 34.423 | 116.787 | 5.4 | Lake Muir at a depth of |