A new study published in Scientific Reports has modelled Sydney’s tsunami risk and the possible consequences if one were to make impact with the Harbour City. The researchers modelled the effects of tsunamis of varying magnitudes and each event was assigned Average Recurrence Intervals (ARI) which indicate how often tsunamis of different sizes are likely to occur. The wave sequences modelled in these scenarios reach heights of 1.4 m and are considered to have a 1.5% chance of occurring over a 70-year lifetime. The predicted levels discussed here seem minor compared to a historical 40 m tsunami which was thought by researchers to have occurred in northern NSW (FM March 2005). The researchers also found that a tsunami which is large enough to roughly flood across Manly is estimated to have a 12% chance of occurring over an average lifetime or an ARI of 550. It was concluded that a large tsunami in Australia is unlikely but possible (read more here and here).