Experts have warned Sydneysiders to expect a tsunami within their lifetime. Photo / 123RF
Experts have warned Sydneysiders to expect a tsunami within their lifetime. Photo / 123RF
Sydneysiders have been warned to expect a tsunami within their lifetime, as the threat of a "dangerous" wave hitting the city is "very real".
Australia's most populous city has an exposed harbour, meaning there is potential for a tsunami to threaten up to 1.5 million people and impact the entire New South Wales coast, according to a paper published in Nature's Scientific Reports.
Research conducted by the University of Newcastle and the Australian Bureau of Meteorology said a wave could be triggered by an earthquake in New Zealand or Vanuatu, and would whip up currents in the harbour to a rapid 8m per second, the Daily Mail Australia reported.
The impact of a tsunami from the report.
While the probability of a tsunami hitting Sydney Harbour or other parts of NSW isn't extremely high, the impact would be thoroughly devastating. The team's research highlighted Australia's ill-preparedness.
In 1960, a tsunami generated by the Chile 9.5 magnitude earthquake - the largest earthquake recorded in the 20th century - impacted Sydney by "breaking moorings, vessels being swept into bridges and wharfs, as well as significant scouring and localised coastal erosion".
"A Sydneysider will probably experience a tsunami in their lifetime," Dr Hannah Power, who co-authored the findings, told news.com.au.
The tsunami that hit Sydney Harbour in 1960 was significant. "We could expect a tsunami of a similar size in the harbour once every 50 to 100 years."
In contrast the 2011 9.1 magnitude Tohoku Japanese tsunami was recorded by Sydney Harbour tide gauges but no damage was reported.
The report says a tsunami in Sydney could flood the northern beaches such as Manly and smash jetties, boats and the shoreline. The impact could be felt as far inland as Parramatta in the city's west, almost 30km from the coast.
A map modelling the effects of a tsunami on Sydney Harbour.
The research modelled the effects of tsunami inundation in Sydney and forecast the impact of the smallest and largest tsunamis on the harbour.
Report co-author Kaya Wilson told news.com.au the research was about creating community awareness and making sure people took tsunami warnings seriously.
"It is something that could happen here and could be devastating ... We don't want people to worry, but we want them to be aware it is a very real threat," Wilson said.
"We want people to be aware of it as a hazard because it could be extremely dangerous."
There are two subduction zones closest to Sydney, one being near Vanuatu and the other south of New Zealand, where two tectonic plates meet under the ocean.
If an earthquake was to occur at either one of the zones and created enough tension, the force could push the water and cause a tsunami that could travel the distance to the east coast of Australia, Wilson said.
While the likelihood of a major tsunami impacting NSW is low, if it did happen, a "wall of water" isn't what people would see, he added.
"If it's a really large earthquake it would be a sequence of waves not just one and there would be very quick rising and falling of the water levels," he said.
"It's like the whole ocean is moving up and down."
