New tsunami hazard data released for Tsunami Awareness Day

By Daniel Bishton on 7 November, 2018

Probabilistic Tsunami Hazard Assessment map. Image provided by Geoscience Australia.

Coinciding with the UN’s World Tsunami Awareness Day, Geoscience Australia has published the Probabilistic Tsunami Hazard Assessment 18, the definitive dataset containing the latest modeling on Australia’s tsunami risk.

Believe it or not, there have been over 50 recorded tsunami incidents in Australia since European settlement.

Whilst most of these resulted in dangerous currents and rips rather than land inundation, damage was recorded at the Geraldton marina from the 2004 Indian Ocean tsunami, and coastal areas all around the country will be at increasing risk due to sea level rise caused by climate change.

Released Monday, the Probabilistic Tsunami Hazard Assessment’s 2018 includes data for more than half a million earthquake-tsunami scenarios in Australia.

Geoscience Australia hazard modeller Dr Gareth Davies, who led the project, said that data from tsunamis recorded in the decade since the last update in 2008 have considerably improved the accuracy and utility of the new dataset.

“The new methodologies in the 2018 update have been tested using 10 years of deep ocean tsunami observational data from the Pacific Ocean to confirm they give a realistic depiction of tsunami behaviour,” he said.

“Additionally, it has data for more locations around Australia. This will make it easier for modellers like me to conduct local tsunami studies, including for major Australian offshore islands and territories.”

Dr. Davies said that subduction zone earthquakes in the Pacific and Indian Oceans accounted for the greatest tsunami risk to the Australian coastline — a condition in which one tectonic plate is thrust under another.

“In Australia, the northwest coast in Western Australia is more likely than the east or southwest coast to experience a tsunami due to its proximity to the Indonesia tectonic plate boundary, which has a long, seismically active fault line,” he said.

Dr Davies said that local tsunami studies derived from the 2018 PTHA could be used to inform evidence-based disaster management and evacuation plans, as well as infrastructure planning and mitigation strategies.

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