Ove Arup and Partners, Kowloon Tong Office, Hong Kong
Modelling the attenuation of peak ground velocity for intraplate earthquakes in Australia is faced with numerous challenges including the lack of quality instrumental earthquake data from close distances. Furthermore, the significant variation in the crustal conditions within the Australian continent means that more than one attenuation relationship is required to suit different conditions even though the entire continent is wholly within the Indo-Australasian tectonic plate. The modelling approach adopted in this study is based on a convenient separation of the source, crustal and path attenuation effects in the modelling. Each of these effects is represented by separate component factors. The accuracy of this Component Attenuation Model (CAM) was evaluated using historical Intensity data collected in Australia over the past one hundred years. It can be shown by the analysis of the residuals that CAM provides better predictions of the Intensities and peak ground velocities than a number of commonly used attenuation models. Most recorded Intensity values are in agreement with the CAM calculations within 0.5 Intensity units.