The risk projected for Adelaide relates more to the probability of an earthquake occurring close to the metropolitan region. The most widespread damage which occurred in Adelaide was in 1954, when the smallest of three large earthquakes hit close to the city. This damaged around 3,000 buildings and caused several injuries. Adelaide buildings are not built to withstand high intensity close proximity earthquakes, and have little flexibility. This contributes to the higher degree of danger associated with an earthquake hitting in the future. The average time between major events is thought to be around 180 years, but could be considerably more or less.
The highest level of danger is for the residents of multi-story buildings and those living in old homes. The height of the building amplifies the shockwaves and increases the risk of damage or injury. The older the home is there is the potential for less mortar in the walls holding the bricks together, which could have disastrous consequences such as bricks or whole walls collapsing.
Image from: http://www.seismicity.see.uwa.edu.au/welcome/seismicity_in_australia#SAeqs
Image from: http://www.seismicity.see.uwa.edu.au/welcome/seismicity_in_australia#SAeqs
However, the 1954 quake demonstrated that metropolitan Adelaide is sitting on firmer, stiff sediments which is less susceptible to dramatic shaking of the ground, but some amplification will still occur. There is also the risk of deeper, softer sediment underneath the tall buildings of Adelaide causing markedly more amplification with the potential for damage. The 1954 earthquakes intensity map also shows no regions of specifically high amplification.
Earthquakes Among us 