Just yesterday I posted an article about how many things build up slowly then turn into something that happens quickly.
The earthquake that occurred today at 9:15am local time is a perfect example of this sort of dynamic. The Australian land mass moves northward at around 7 centimeters a year, it then collides into the tectonic plates Northwards. This creates an enormous amount of compressive force over time. Eventually that can be released via earthquakes. The slowness of geological changes that leads up to these earthquakes is remarkable just as the speed at which the energy is released, when it is finally released, is fast.
Earthquakes in Australia are somewhat common at smaller intensities and happen all over the place. Powerful earthquakes are very uncommon here though. You have to go back to the 1989 Newcastle Earthquake to see something of similar intensity.
As a result of powerful earthquakes being rare people here don't know how to react. I immediately went to assess structural damages and check for fires. Thankfully there were no fires, also thankfully single story timber construction buildings tend to fare quite well in these situations. So far it seems there has not been a whole lot of damage in Melbourne from this, a few brick walls have collapsed but that appears to be about it.