Australia is not on the edge of any plate. So why do we have earthquakes?
The reason is that the Australian plate is being pushed to the north and it is colliding with other plates. As a result we don't get strong earthquakes very often. One with a magnitude of more than 7 on the richter scale occurs once every 100000 years. In other Parts of the world an earthquake with a magnitude of more than 7 might happen once every 100 years, or less.
Earthquake Hazards Map.
It's not that we don't get any strong earthquakes. The strongest earthquake recorded was in a remote town in Western Australia, on April 29, 1941, in Meeberrie. With a magnitude of 7.2, if it had hit a major built up area, it would have cause major damage. The second strongest earthquake in Australia was at Meckering, a small town south-west of Perth on October 14, 1968. This earthquake bent train tracks and caused some minor damage in Perth 150km away.
Bent rails caused by the meckering earthquake.
The biggest earthquake not in Western Australia was at Tennant Creek, NT on 22 January, 1988. Three earthquakes, all over a magnitude of 6, happened in one day. Large ground cracks and a 35km fault line was created on that day. Whats more, the pipeline between Darwin and Alice Springs was shortened by a metre.
Fault caused by the earthquakes at Tenant Creek.