The last tsunami that had a significant impact on Australia’s east coast occurred almost 60 years ago in May 1960.
Triggered by an earthquake in Chile, the resulting tsunami caused significant tidal surges in Sydney and Newcastle. The 0.5 metre surge in Newcastle harbour was strong enough to capsize a fishing boat in Throsby basin.
In Sydney, dangerous whirlpools were reported occurring east of the Spit bridge.
New research conducted by the University of Newcastle shows that, while these events are extremely rare, the potential impact of a tsunami on the NSW coast could have life threatening consequences.
Mapping of Sydney harbour shows a fast moving tsunami could result in unpredictable water movements that pose a threat to swimmers, boaters and those near the water.
Low-lying areas around Newcastle harbour such as Stockton, Carrington, Wickham and Mayfield would be particularly at risk if such as scenario occurred in Newcastle Harbour.
State Emergency Services mapping conducted in 2016 suggests inundation could reach up to 10 kilometres from the harbour to areas such as Hexham.
Unfortunately the University of Newcastle research also highlighted that the level of community awareness about the risk of a tsunami is relatively low.
Perhaps the fact that there is only a one per cent chance of a tsunami occurring each year has contributed to the lack of awareness.
But as tsunami researcher Dr Hannah Power points out “If you translate that into something people might put more emphasis on, like their health, if there was a one per cent risk of a medical procedure going horribly wrong, you might rethink whether you wanted to have the operation.”
Even though the risk is small, appropriate planning needs to be done to ensure the coastal communities are equipped to deal with a tsunami surge.
Existing SES guidelines include a ‘red zone’, which includes low-lying parts of Newcastle. In the event of a tsunami alert people in this area are asked to move 10 metres up into a sturdy concrete building.
The new research is a welcome addition and will help improve tsunami awareness and preparedness. Forewarned is forearmed, especially in an emergency.
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