Making sense of Australian earthquakes: the Ambraseys legacy

Through his students, Professor Nick Ambraseys has had a strong impact on the introduction of earthquake engineering practices in Australia, including historical earthquake studies, strong motion instrumentation and analysis, foundation studies including liquefaction, and building code formulation. In Australia the process of upgrading the third and current edition of the earthquake code and hazard map has begun. There are now about 150 digital strong motion recorders installed in cities, on major structures and at Australian National Seismograph Network sites. Three volumes of an isoseismal atlas have been published totalling more than 300 maps, mainly historical earthquakes. Significant progress has been made in paleoseismological studies across the continent, adding to the complexity of the intraplate seismicity model. With time and more installed accelerographs, the peak ground acceleration recorded in Australia has increased from .25 g in 1984 to .5 g in 1988 and 1 g in 1994, all from earthquakes smaller than magnitude 5, supporting Ambraseys contention that PGA alone is not a suitable parameter for a design ground motion.