Mr Broadbent cited "unprecedented" and "uncertain" times as the key factors behind his decision, and insisted he still had the stamina to carry out his duties.
Geoscience Australia says Darwin and the Latrobe Valley are more likely to experience "strong ground shaking". The latter is among the sites the Coalition has identified as a potential home for a nuclear reactor.
Scientists are fortifying a national park at the southern tip of Australia's mainland to keep invasive predators away from endangered native plants and animals.
The Australian Workers' Union wants the government to scrap its plans to offload management of two popular Victorian ski resorts to a private operator.
Georgia, 17, was diagnosed with epilepsy as a child but says a regular small dose of medicine and staying calm by listening to her favourite tunes has helped her become seizure-free.
Victoria's chief health officer warns there is a high risk of epidemic thunderstorm asthma in the North Central and West and South Gippsland forecast districts.